Control of Air Pollution From New Motor Vehicles and New Motor Vehicle Engines; Regulations Requiring Onboard Diagnostic Systems on 2010 and Later Heavy-Duty Engines Used in Highway Applications Over 14,000 Pounds; Revisions to Onboard Diagnostic Requirements for Diesel Highway Heavy-Duty Vehicles Under 14,000 Pounds

[Federal Register: January 24, 2007 (Volume 72, Number 15)]
[Proposed Rules]
[Page 3249-3298]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24ja07-31]

[[pp. 3249-3298]]
Control of Air Pollution From New Motor Vehicles and New Motor
Vehicle Engines; Regulations Requiring Onboard Diagnostic Systems on
2010 and Later Heavy-Duty Engines Used in Highway Applications Over
14,000 Pounds; Revisions to Onboard Diagnostic Requirements f[[Page 3249]]

[[Continued from page 3248]]

[[Page 3249]]

variable geometry turbo position, commanded variable geometry turbo
position, turbocharger compressor inlet temperature, turbocharger
compressor inlet pressure, turbocharger turbine inlet temperature,
turbocharger turbine outlet temperature, wastegate valve position, glow
plug lamp status, oxygen sensor output, air/fuel ratio sensor output,
NO_X sensor output, and evaporative system vapor pressure.
---------------------------------------------------------------------------

\47\ Note that, for purposes of the calculated load and torque
parameters for diesel engines, manufacturers would be required to
report the most accurate values that are calculated within the
applicable electronic control unit (e.g., the engine control
computer). ``Most accurate values,'' in this context, would be those
of sufficient accuracy, resolution, and filtering that they could be
used for the purpose of in-use emissions testing with the engine
still in a vehicle (e.g., using portable emissions measurement
equipment).
---------------------------------------------------------------------------

We are also proposing requirements for storage of ``freeze frame''
information at the time a malfunction is detected and a DTC is stored.
The freeze frame provides the operating conditions of the vehicle at
the time of malfunction detection and the DTC associated with the data.
The parameters we are proposing for inclusion in the freeze frame are a
subset of the parameters listed above for the data stream. Note that
storage of only one freeze frame would be required. Manufacturers may
choose to store additional frames, provided that the required frame can
be read using a scan tool meeting SAE J1978 specifications or designed
to communicate with an SAE J1939 network.
We are also proposing that the OBD system store the most recent
monitoring results for most of the major monitors. Manufacturers would
be required to store and make available to the scan tool certain test
information--i.e., the minimum and maximum values that should occur
during proper operation along with the actual test value--of the most
recent monitoring event. ``Passing'' systems would store test results
that are within the test limits, while ``failing'' systems would store
test results that are outside the test limits. The storage of test
results would assist technicians in diagnosing and repairing
malfunctions and would help distinguish between components that are
performing well below the malfunction thresholds from those that are
passing the malfunction thresholds marginally.
viii. Identification Numbers
We are also proposing that manufacturers be required to report two
identification numbers related to the software and specific calibration
values in the onboard computer. The first item, Calibration
Identification Number (CAL ID), would identify the software version
installed in the onboard computer. Software is often changed following
production of the engine. These software changes often make changes to
the emissions control system or the OBD system. We are proposing that
these changes include a new CAL ID and that it be communicated via the
diagnostic connector to the scan tool. The second item, Calibration
Verification Number (CVN), would help to ensure that the current
software has not been corrupted, modified inappropriately, or otherwise
tampered with. Both CAL ID and CVN help ensure the integrity of the OBD
system. The CVN proposal would require manufacturers to develop
sophisticated software algorithms that would essentially be a self-
check calculation of all of the emissions-related software and
calibration values in the onboard computer and would return the result
of the calculation to a scan tool. If the calculated result did not
equal the expected result for that CAL ID, one would know that the
software had been corrupted or otherwise modified. The CVN result would
have to be made available at all times to a generic scan tool.
We are also proposing that the Vehicle Identification Number (VIN)
be communicated via the diagnostic connector to a generic scan tool in
a standardized format. The VIN would be a unique number assigned by the
vehicle manufacturer to every vehicle built. The VIN is commonly used
for purposes of ownership and registration to uniquely identify every
vehicle. By requiring the VIN to be stored in the onboard computer and
available electronically to a generic scan tool, the possibility of a
fraudulent inspection (e.g., by plugging into a different vehicle than
an inspection citation was issued originally to generate a proof of
correction) would be minimized. Electronic access to this number would
also simplify the inspection process and reduce transcription errors
from manual data entry.
We are proposing that the VIN be electronically stored in a control
module on the vehicle, but not that it necessarily be stored in the
engine control module. As long as the VIN is reported correctly and
according to the selected reference document standards, we consider it
irrelevant as to which control module (e.g., engine controller,
instrument cluster controller) contains the information. Further, we
are proposing that the ultimate responsibility would lie with the
engine manufacturer to ensure that every vehicle manufactured with one
of its engines satisfies this requirement. However, we would expect
that the physical task of implementing this requirement would likely be
passed from the engine manufacturer to the vehicle manufacturer via an
additional build specification. Thus, analogous to how the engine
manufacturer currently provides engine purchasers with detailed
specifications regarding engine cooling requirements, additional sensor
inputs, physical mounting specifications, weight limitations, etc., the
engine manufacturer would likely include an additional specification
dictating the need for the VIN to be made available electronically. It
would be left to each engine manufacturer to determine the most
effective method to achieve this, as long as the VIN requirement is
met. Some manufacturers may find it most effective to provide the
capability in the engine control module delivered with the engine
coupled with a mechanism for the vehicle manufacturer to program the
module with the VIN upon installation of the engine into an actual
vehicle. Others may find it more effective to require the vehicle
manufacturer to have the capability built into other modules installed
on the vehicle such as instrument cluster modules, etc. We are aware of
several current vehicles with engines from three different engine
manufacturers that already have the VIN available through engine-
manufacturer specific scan tools; this indicates that such arrangements
already exist in one form or another and that they are working.
5. In-Use Performance Ratio Tracking Requirements
To separately report an in-use performance ratio for each
applicable monitor as discussed in sections II.B through II.D, we are
proposing that manufacturers be required to implement software
algorithms to report a numerator and denominator in the standardized
format specified below and in accordance with the specifications of the
reference documents listed in section II.F.1.
For the numerator, denominator, general denominator, and ignition
cycle counter:
? Each number must have a minimum value of zero and a
maximum value of 65,535 with a resolution of one.
? Each number must be reset to zero only when a non-volatile
random access memory (NVRAM) reset occurs (e.g., reprogramming event)
or, if the numbers are stored in keep-alive memory (KAM), when KAM is
lost due to an interruption in electrical power to the control module
(e.g., battery disconnect). Numbers may not be reset to zero under any
other circumstances including when commanded to do so via a scan tool
command to clear DTCs or reset KAM.
? If either the numerator or denominator for a specific
component reaches the maximum value of 65,535 ±2, both
numbers should be divided by two before either is incremented again to
avoid overflow problems.

[[Page 3250]]

? If the ignition cycle counter reaches the maximum value of
65,535 ±2, the ignition cycle counter should rollover and
increment to zero on the next ignition cycle to avoid overflow problems.
? If the general denominator reaches the maximum value of
65,535 ±2, the general denominator should rollover and
increment to zero on the next drive cycle that meets the general
denominator definition to avoid overflow problems.
? If an engine is not equipped with a component (e.g.,
oxygen sensor bank 2, secondary air system), the corresponding
numerator and denominator for that specific component should always be
reported as zero.
For the in-use performance ratio:
? The ratio should have a minimum value of zero and a
maximum value of 7.99527 with a resolution of 0.000122.
? A ratio for a specific component should be considered to
be zero whenever the corresponding numerator is equal to zero and the
corresponding denominator is not zero.
? A ratio for a specific component should be considered to
be the maximum value of 7.99527 if the corresponding denominator is
zero or if the actual value of the numerator divided by the denominator
exceeds the maximum value of 7.99527.
For engine run time tracking on all gasoline and diesel engines,
manufacturers would be required to implement software algorithms to
individually track and report in a standardized format the engine run
time while being operated in the following conditions:
? Total engine run time
? Total idle run time (with ``idle'' defined as accelerator
pedal released by driver, vehicle speed less than or equal to one mile
per hour, and PTO not active);
? Total run time with PTO active.
Each of the above engine run time counters would have the following
numerical value specifications:
? Each numerical counter must be a four-byte value with a
minimum value of zero at a resolution of one minute per bit.
? Each numerical counter must be reset to zero only when a
nonvolatile memory reset occurs (e.g., a reprogramming event).
Numerical counters cannot be reset to zero under any other
circumstances including a scan tool (generic or enhanced) command to
clear DTCs or reset KAM.
? When any of the individual numerical counters reaches its
maximum value, all counters must be divided by two before any are
incremented again. This is meant to avoid overflow problems.
6. Exceptions to Standardization Requirements
For alternative-fueled engines derived from a diesel-cycle engine,
we are proposing that the manufacturer be allowed to meet the
standardized requirements discussed in this section that are applicable
to diesel engines rather than meeting the requirements applicable to
gasoline engines.

G. Implementation Schedule, In-Use Liability, and In-Use Enforcement

1. Implementation Schedule and In-Use Liability Provisions
Table II.G-1 summarizes the proposed implementation schedule for
the OBD monitoring requirements--i.e., the proposed certification
requirements and in-use liabilities. More detail regarding the
implementation schedule and liabilities can be found in the sections
that follow.

Table II.G-1.--OBD Certification Requirements and In-use Liability for
Diesel Fueled and Gasoline Fueled Engines over 14,000 Pounds: Monitoring
Requirements
------------------------------------------------------------------------
Certification
Model year Applicability requirement In-use liability
------------------------------------------------------------------------
2010-2012......... Parent rating Full liability Full liability
within 1 to thresholds to 2x
compliant according to thresholds. \c\
engine family. certification
\a\ demonstration
procedures. \b\
Child ratings Certification Liability to
within the documentation monitor and
compliant only (i.e., no detect as noted
engine family. certification in
demonstration); certification
no liability to documentation.
thresholds.
All other engine None............ None.
families and
ratings.
2013-2015......... Parent rating Full liability Full liability
from 2010-2012 to thresholds to 2x
and parent according to thresholds.
rating within 1- certification
2 additional demonstration
engine families. procedures.
Child ratings Full liability Full liability
from 2010-2012 to thresholds to 2x
and parent but thresholds.
ratings from certification
any remaining documentation
engine families only.
or OBD
groups.\d\
Additional Certification Liability to
engine ratings. documentation monitor and
only; no detect as noted
liability to in
thresholds. certification
demonstration.
2016-2018........ One rating from Full liability Full liability
1-3 engine to thresholds to thresholds.
families and/or according to
OBD groups. certification
demonstration
procedures.
Remaining Full liability Full liability
ratings. to thresholds to 2x
but thresholds.
certification
documentation
only.
2019+............. One rating from Full liability Full liability
1-3 engine to thresholds to thresholds.
families and/or according to
OBD groups. certification
demonstration
procedures.
Remaining Full liability Full liability
ratings. to thresholds to thresholds.
but
certification
documentation
only.
------------------------------------------------------------------------
Notes: (a) Parent and child ratings are defined in section II.G; which
rating(s) serves as the parent rating and which engine families must
comply is not left to the manufacturer, as discussed in section II.G.
(b) The certification demonstration procedures and the certification
documentation requirements are discussed in section VIII.B. (c) Where
in-use liability to thresholds and 2x thresholds is noted,
manufacturer liability to monitor and detect as noted in their
certification documentation is implied. (d) OBD groups are groupings
of engine families that use similar OBD strategies and/or similar
emissions control systems, as described in the text.

For the 2010 through 2012 model years, manufacturers would be
required to implement OBD on one engine family. All other 2010 through
2012 engine families would not be subject to any OBD requirements
unless otherwise required to do so (e.g., to demonstrate that SCR
equipped vehicles will not be operated without urea). For 2013,

[[Page 3251]]

manufacturers would be required to implement OBD on all engine families.
We are proposing this implementation schedule for several reasons.
First, industry has made credible arguments that their resources are
stretched to the limit developing and testing strategies for compliance
with the 2007/2010 heavy-duty highway emissions standards. We do not
want to jeopardize their success toward that goal by being too
aggressive with our OBD program. Second, OBD is a complex and difficult
regulation with which to comply. We believe that our implementation
schedule would give industry the opportunity to introduce OBD systems
on a limited number of engines giving them and us very valuable
learning experience. Should mistakes or errors in regulatory
interpretation occur, the ramifications would be limited to only a
subset of the new vehicle fleet rather than the entire new vehicle
fleet. Lastly, the proposed OBD requirements outlined above, and the
production vehicle evaluation provisions discussed in Section VIII,
reflect 10 to 20 years of learning by EPA, CARB, and industry
(primarily the light-duty gasoline industry) as to what works and what
does not work. This is, perhaps, especially true for those OBD elements
that involve the interface between the OBD system and service and I/M
inspection personnel. Gasoline manufacturers have had the ability to
evolve their OBD systems along with this learning process. However,
diesel engine manufacturers have not really been involved in this
learning process and, as a result, 100 percent implementation in 2010
would be analogous to implementing 10 to 20 years of OBD learning in
one implementation step. We believe that implementing in two or three
gradual steps rather than one big step will benefit everyone involved.
Table II.G-1 makes reference to ``parent'' and ``child'' ratings.
In general, engine manufacturers certify an engine family that consists
of several ratings having slightly different horsepower and/or torque
characteristics but no differences large enough to require a different
engine family designation. For emissions certification, the parent
rating--i.e., the rating for which emissions data are submitted to EPA
for the purpose of demonstrating emissions compliance--is defined as
the ``worst case'' rating. This worst case rating is the rating
considered as having the worst emissions performance and, therefore,
its compliance demonstrates that all other ratings within the family
must comply. For OBD purposes, we wanted to limit the burden on
industry--hence the proposal for only one compliant engine family in
2010--yet maximize the impact of the OBD system. Therefore, for model
years 2010 through 2012, we are defining the OBD parent rating as the
rating having the highest weighted projected sales within the engine
family having the highest weighted projected sales, with sales being
weighted by the useful life of the engine rating. Table II.G-2 presents
a hypothetical example for how this would work. Using this approach,
the OBD compliant engine family in 2010 would be the engine family
projected to produce the most in-use emissions (based on sales weighted
by expected miles driven). Likewise, the fully liable parent OBD rating
would be the rating within that family projected to produce the most
in-use emissions.

Table II.G-2.--Hypothetical Example of How the OBD Parent and Child Ratings Would Be Determined
--------------------------------------------------------------------------------------------------------------------------------------------------------
OBD weighting-- OBD weighting--
Projected Certified engine rating \a\ engine family \b\
OBD group Engine family Rating sales useful life (billions) (billions)

--------------------------------------------------------------------------------------------------------------------------------------------------------
I............................................ A 1 10,000 285,000 2.85 14.25
........................ 2 40,000 285,000 11.4 .................
B 1 10,000 435,000 4.35 21.60
........................ 2 20,000 435,000 8.70 .................
........................ 3 30,000 285,000 8.55 .................
II........................................... C 1 20,000 110,000 2.20 7.70
........................ 2 50,000 110,000 5.50 .................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: (a) For engine family A, rating 1, 10,000 x 285,000 / 1 billion = 2.85.
(b) For engine family A, 2.85 + 11.4 = 14.25.

In the example shown in Table II.G-2, the compliant engine family
in 2010 would be engine family B and the parent OBD rating within that
family would be rating 2. The other OBD compliant ratings within engine
family B would be dubbed the ``child'' ratings. For model years 2013
through 2015, the parent ratings would be those ratings having the
highest weighted projected sales within each of the one to three engine
families having the highest weighted projected sales, with sales being
weighted by the useful life of the engine rating. In the example shown
in Table II.G-2, the parent ratings would be rating 2 of engine family
A, rating 2 of engine family B, and rating 2 of engine family C (Note
that this is only for illustration purposes since our proposal would
not require that a manufacturer with only three engine families have
three parent ratings and instead would require only one).
The manufacturer would not need to submit test data demonstrating
compliance with the emissions thresholds for the child ratings. We
would fully expect these child ratings to use OBD calibrations--i.e.,
malfunction trigger points--that are identical or nearly so to those
used on the parent rating. However, we would allow manufacturers to
revise the calibrations on their child ratings where necessary so as to
avoid unnecessary or inappropriate MIL illumination. Such revisions to
OBD calibrations have been termed ``extrapolated'' OBD calibrations
and/or systems. The revisions to the calibrations on child ratings and
the rationale for them would need to be very clearly described in the
certification documentation.
For the 2013 and later model years, we are proposing that
manufacturers certify one to three parent ratings. The actual number of
parent ratings would depend upon the manufacturer's fleet and would be
based on both the emissions control system architectures present in
their fleet and the similarities/differences of the engine families in
their fleet. For example, a manufacturer that uses a DPF with
NO_X adsorber on each of the engines would have only one
system architecture. Another manufacturer that uses a DPF with
NO_X adsorber on some engines and a DPF with SCR on others
would have at least two architectures. We would expect that
manufacturers would group similar architectures and similar engine

[[Page 3252]]

families into so called ``OBD groups.'' These OBD groups would consist
of a combination of engines, engine families, or engine ratings that
use the same OBD strategies and similar calibrations. The manufacturer
would be required to submit details regarding their OBD groups as part
of their certification documentation that shows the engine families and
engine ratings within each OBD group for the coming model year. While a
manufacturer may end up with more than three OBD groups, we do not
intend to require a parent rating for more than three OBD groups.
Therefore, in the example shown in Table II.G-2, rather than submitting
test data for the three parent ratings as suggested above, the OBD
grouping would result in the parent ratings being rating 2 of engine
family B and rating 2 of engine family C. These parents would represent
OBD groups I and II, and the manufacturer's product line. For 2013
through 2015, we intend to allow the 2010 parent to again act as a
parent rating and, provided no significant changes had been made to the
engine or its emissions control system, complete carryover would be
possible. However, for model years 2016 and beyond, we would work
closely with CARB staff and the manufacturer to determine the parent
ratings so that the same ratings are not acting as the parents every
year. In other words, our definitions for the OBD parent ratings as
discussed here apply only during the years 2010 through 2012 and again
for the years 2013 through 2015. We request comment on this approach.
In addition to this gradual certification implementation schedule,
we are proposing some relaxations for in-use liability during the 2010
through 2018 model years. The first such relaxation is higher interim
in-use compliance standards for those OBD monitors calibrated to
specific emissions thresholds. For the 2010 through 2015 model years,
an OBD monitor on an in-use engine would not be considered non-
compliant (i.e., subject to enforcement action) unless emissions
exceeded twice the OBD threshold without detection of a malfunction.
For example, for an EGR monitor on an engine with a NO_X FEL
of 0.2 g/bhp-hr and an OBD threshold of 0.5 g/bhp-hr (i.e., the
NO_X FEL+0.3), a manufacturer would not be subject to
enforcement action unless emissions exceeded 1.0 g/bhp-hr
NO_X without a malfunction being detected. For the model
years 2016 through 2018, parent ratings would be liable to the
certification emissions thresholds, but child ratings and other ratings
would remain liable to twice the certification thresholds. Beginning in
the 2019 model year, all families and all ratings would be liable to
the certification thresholds.
The second in-use relaxation is a limitation in the number of
engines that would be liable for in-use compliance with the OBD
emissions thresholds. For 2010 through 2012, we are proposing that
manufacturers be fully liable in-use to twice the thresholds for only
the OBD parent rating. The child ratings within the compliant engine
family would have liability for monitoring in the manner described in
the certification documentation, but would not have liability for
detecting a malfunction at the specified emissions thresholds. For
example, a child rating's DPF monitor designed to operate under
conditions X, Y, and Z and calibrated to detect a backpressure within
the range A to B would be expected to do exactly that during in-use
operation. However, if the tailpipe emissions of the child engine were
to exceed the applicable OBD in-use thresholds (i.e., 2x the
certification thresholds during 2010-2015), despite having a
backpressure within range A to B under conditions X, Y, and Z, there
would be no in-use OBD failure nor cause for enforcement action. In
fact, we would expect the OBD monitor to determine that the DPF was
functioning properly since its backpressure was in the acceptable
range. For model years 2013 through 2015, this same in-use relaxation
would apply to those engine families that do not lie within an engine
family for which a parent rating has been certified. For 2016 and later
model years, all engines would have some in-use liability to
thresholds, either the certification thresholds or twice those thresholds.
These in-use relaxations are meant to provide ample time for
manufacturers to gain experience without an excessive level of risk for
mistakes. They would also allow manufacturers to fine-tune their
calibration techniques over a six to ten year period.
We are also proposing some a specific implementation schedule for
the standardization requirements discussed in section II.F. We
initially intended to require that any compliant OBD engine family
would be required to implement all of the standardization requirements.
However, we became concerned that, during model years 2010 through
2012, we could have a situation where OBD compliant engines from
manufacturer A might be competing against non-OBD engines from
manufacturer B for sales in the same truck. In such a case, the truck
builder would be placed in a difficult position of needing to design
their truck to accommodate OBD compliant engines--along with a
standardized MIL, a specific diagnostic connector location
specification, etc.--and non-OBD engines. After consideration of this
almost certain outcome, we have decided to limit the standardization
requirements that must be met during the 2010 through 2012 model years.
Beginning in 2013, all engines will be OBD compliant and this would
become a moot issue. Table II.G-3 shows the proposed implementation
schedule for standardization requirements.

Table II.G-3.--OBD Standardization Requirements for Diesel Fueled and
Gasoline Fueled Engines Over 14,000 Pounds
------------------------------------------------------------------------
Required Waived
Model year Applicability standardization standardization
features features
------------------------------------------------------------------------
2010-2012......... Parent and Child Emissions Standardized
ratings within related connector
1 compliant (II.F.4) except (II.F.2).
engine family. for the Dedicated
\a\ requirement to (i.e.,
make the data regulated OBD-
available in a only) MIL.
standardized Communication
format or in protocols
accordance with (II.F.3).
SAE J1979/1939 Emissions
specifications) related
. MIL functions
activation and (II.F.4) with
deactivation.\b respect to the
\ Performance requirement to
tracking--calcu make the data
lation of available in a
numerators, standardized
denominators, format or in
ratios. accordance with
SAE J1979/1939
specifications)
Other engine None............ All.
families.
2013+............. All engine All............. None.
families and
ratings.
------------------------------------------------------------------------
Notes: (a) Parent and child ratings are defined in section II.G; which
rating serves as the parent rating and which engine families must
comply is not left to the manufacturer, as discussed in section II.G.
(b) There would be no requirement for a dedicated MIL and no
requirement to use a specific MIL symbol, only that a MIL be used and
that it use the proposed activation/deactivation logic.

[[Page 3253]]

2. In-Use Enforcement
When conducting our in-use enforcement investigations into OBD
systems, we intend to use all tools we have available to analyze the
effectiveness and compliance of the system. These tools may include on-
vehicle emission testing systems such as the portable emissions
measurement systems (PEMS). We would also use scan tools and data
loggers to analyze the data stream information to compare real world
operation to the documentation provided at certification.
Importantly, we would not intend to pursue enforcement action
against a manufacturer for not detecting a failure mode that could not
have been reasonably predicted or otherwise detected using monitoring
methods known at the time of certification. For example, we are
proposing a challenging set of requirements for monitoring of DPF
systems. As of today, engine manufacturers are reasonably confident in
their ability to detect certain DPF failure modes at or near the
proposed thresholds--e.g., a leaking DPF resulting from a cracked
substrate--but are not confident in their ability to detect some other
DPF failure modes--e.g., a leaking DPF resulting from a partially
melted substrate. If a partially melted substrate indeed cannot be
detected and this is known during the certification process, we cannot
expect such a failure to be detected on an in-use vehicle.
We also want to make it clear who would be the responsible party
should we pursue any in-use enforcement action with respect to OBD. We
are very familiar with the heavy-duty industry and its tendency toward
separate engine and component suppliers. This contrasts with the light-
duty industry which tends toward a more vertically integrated
structure. The non-vertically integrated nature of the heavy-duty
industry can present unique difficulties for OBD implementation and for
OBD enforcement. With the complexity of OBD systems, especially those
meeting the requirements being proposed today, we would expect the
interactions between the various parties involved--engine manufacturer,
transmission manufacturer, vehicle manufacturer, etc.--to be further
complicated. Nonetheless, in the end the vast majority of the proposed
OBD requirements would apply directly to the engine and its associated
emission controls, and the engine manufacturer would have complete
responsibility to ensure that the OBD system performs properly in-use.
Given the central role the engine and engine control unit would play in
the OBD system, we are proposing that the party certifying the engine
and OBD system (typically, the engine manufacturer) be the responsible
party for in-use compliance and enforcement actions. In this role, the
certifying party would be our sole point of contact for potential
noncompliances identified during in-use or enforcement testing. We
would leave it to the engine manufacturer to determine the ultimate
party responsible for the potential noncompliance (e.g., the engine
manufacturer, the vehicle manufacturer, or some other supplier). In
cases where remedial action such as an engine recall would be required,
the certifying party would take on the responsibility of arranging to
bring the engines or OBD systems back into compliance. Given that
heavy-duty engines are already subject to various emission requirements
including engine emission standards, labels, and certification, engine
manufacturers currently impose restrictions via signed agreements with
engine purchasers to ensure that their engines do not deviate from
their certified configuration when installed. We would expect the OBD
system's installation to be part of such agreements in the future.

H. Proposed Changes to the Existing 8,500 to 14,000 Pound Diesel OBD
Requirements

We are also proposing changes to our OBD requirements for diesel
engines used in heavy-duty vehicles under 14,000 pounds (see 40 CFR
86.005-17 for engine-based requirements and 40 CFR 86.1806-05 for
vehicle or chassis-based requirements). Table II.H-1 summarizes the
proposed changes to under 14,000 pound heavy-duty diesel emissions
thresholds at which point a component or system has failed to the point
of requiring an illuminated MIL and a stored DTC. Table II.H-2
summarizes the proposed changes for diesel engines used in heavy-duty
applications under 14,000 pounds. The proposed changes are meant to
maintain consistency with the diesel OBD requirements we are proposing
for over 14,000 pound applications.

Table II.H-1.--Proposed New, or Proposed Changes to Existing, Emissions Thresholds for Diesel Fueled CI Heavy-
duty Vehicles Under 14,000 Pounds (g/mi)
----------------------------------------------------------------------------------------------------------------
Component/monitor MY NMHC CO NOX PM
----------------------------------------------------------------------------------------------------------------
NMHC catalyst system......... 2010-2012..... 2.5x.
2013+......... 2x.
NOX catalyst system.......... 2007-2009..... .............. .............. 3x............
2010+......... .............. .............. +0.3.
DPF system................... 2010-2012..... 2.5x.......... .............. .............. 4x.
2013+......... 2x............ .............. .............. +0.04.
Air-fuel ratio sensors 2007-2009..... 2.5x.......... 2.5x.......... 3x............ 4x.
upstream.
2010-2012..... 2.5x.......... 2.5x.......... +0.3.......... +0.02.
2013+......... 2x............ 2x............ +0.3.......... +0.02.
Air-fuel ratio sensors 2007-2009..... 2.5x.......... .............. 3x............ 4x.
downstream.
2010-2012..... 2.5x.......... .............. +0.3.......... 4x.
2013+......... 2x............ .............. +0.3.......... +0.04.
NOX sensors.................. 2007-2009..... .............. .............. 4x............ 5x.
2010-2012..... .............. .............. +0.3.......... 4x.
2013+......... .............. .............. +0.3.......... +0.04.
``Other monitors'' with 2007-2009..... 2.5x.......... 2.5x.......... 3x............ 4x.
emissions thresholds.
2010-2012..... 2.5x.......... 2.5x.......... +0.3.......... 4x.
2013+......... 2x............ 2x............ +0.3.......... +0.02.
----------------------------------------------------------------------------------------------------------------
Notes: MY=Model Year; 2.5x means a multiple of 2.5 times the applicable emissions standard; +0.3 means the
standard plus 0.3; not all proposed monitors have emissions thresholds but instead rely on functionality and
rationality checks as described in section II.D.4.

[[Page 3254]]

Table II.H-2.--Proposed New, or Proposed Changes to Existing, Emissions Thresholds for Diesel Fueled CI Engines Used in Heavy-duty Vehicles Under 14,000
Pounds (g/bhp-hr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Component/Monitor MY Std/FEL NMHC CO NOX PM
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMHC catalyst system............. 2010-2012......... All............... 2.5x.
2013+............. All............... 2x.
NOX catalyst system.............. 2007-2009......... >0.5 NOX.......... ................. ................. 1.75x.
2007-2009......... < =0.5 NOX......... ................. ................. +0.5.
2010+............. All............... ................. ................. +0.3.
DPF system....................... 2010-2012......... All............... 2.5x............. ................. ................. 0.05/+0.04.
2013+............. All............... 2x............... ................. ................. 0.05/+0.04.
Air-fuel ratio sensors upstream.. 2007-2009......... >0.5 NOX.......... 2.5x............. 2.5x............. 1.75x............ 0.05/+0.04.
2007-2009......... < =0.5 NOX......... 2.5x............. 2.5x............. +0.5............. 0.05/+0.04.
2010-2012......... All............... 2.5x............. 2.5x............. +0.3............. 0.03/+0.02.
2013+............. All............... 2x............... 2x............... +0.3............. 0.03/+0.02.
Air-fuel ratio sensors downstream 2007-2009......... >0.5 NOX.......... 2.5x............. ................. 1.75x............ 0.05/+0.04.
2007-2009......... < =0.5 NOX......... 2.5x............. ................. +0.5............. 0.05/+0.04.
2010-2012......... All............... 2.5x............. ................. +0.3............. 0.05/+0.04.
2013+............. All............... 2x............... ................. +0.3............. 0.05/+0.04.
NOX sensors...................... 2007-2009......... >0.5 NOX.......... ................. ................. 1.75x............ 0.05/+0.04.
2007-2009......... < =0.5 NOX......... ................. ................. +0.5............. 0.05/+0.04.
2010+............. All............... ................. ................. +0.3............. 0.05/+0.04.
``Other monitors'' with emissions 2007-2009......... >0.5 NOX.......... 2.5x............. 2.5x............. 1.75x............ 0.05/+0.04.
thresholds.
2007-2009......... < =0.5 NOX......... 2.5x............. 2.5x............. +0.5............. 0.05/+0.04.
2010-2012......... All............... 2.5x............. 2.5x............. +0.3............. 0.03/+0.02.
2013+............. All............... 2x............... 2x............... +0.3............. 0.03/+0.02.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: MY=Model Year; 2.5x means a multiple of 2.5 times the applicable emissions standard or family emissions limit (FEL); +0.3 means the standard or
FEL plus 0.3; 0.05/+0.04 means an absolute level of 0.05 or an additive level of the standard or FEL plus 0.04, whichever level is higher; not all
proposed monitors have emissions thresholds but instead rely on functionality and rationality checks as described in section II.D.4.

1. Selective Catalytic Reduction and Lean NO_X Catalyst Monitoring
We are proposing that the 8,500 to 14,000 pound SCR and lean
NO_X catalyst monitoring requirements mirror those discussed
in section II.B.6. The current regulations require detection of a
NO_X catalyst malfunction before emissions exceed 1.5x the
emissions standards. We no longer believe that such a tight threshold
level is appropriate for diesel SCR and lean NO_X catalyst
systems. We believe that such a tight threshold could result in too
many false failure indications. The required monitoring conditions with
respect to performance tracking (discussed in section II.B.6.c) would
not apply for under 14,000 pound heavy-duty applications since we do
not have performance tracking requirements for under 14,000 pound
applications. We are proposing this change for the 2007 model year.
2. NO_X Adsorber System Monitoring
We are proposing that the 8,500 to 14,000 pound NO_X
adsorber monitoring requirements mirror those discussed in section
II.B.7. The current regulations require detection of a NO_X
adsorber malfunction before emissions exceed 1.5x the emissions
standards. We no longer believe that such a tight threshold level is
appropriate for diesel NO_X adsorber systems. We believe that
such a tight threshold could result in too many false failure
indications. The required monitoring conditions with respect to
performance tracking (discussed in section II.B.7.c) would not apply
for under 14,000 pound heavy-duty applications since we do not have
performance tracking requirements for under 14,000 pound applications.
We are proposing this change for the 2007 model year.
3. Diesel Particulate Filter System Monitoring
We are proposing that the 8,500 to 14,000 pound DPF monitoring
requirements mirror those discussed in section II.B.8. Our current
regulations require detection of a catastrophic failure only. The
proposed monitoring requirements discussed in section II.B.8 would be
far more comprehensive and protective of the environment than would a
catastrophic failure monitor. The required monitoring conditions with
respect to performance tracking (discussed in section II.B.8.c) would
not apply for under 14,000 pound heavy-duty applications since we do
not have performance tracking requirements for under 14,000 pound
applications. We are proposing no changes to the DPF monitoring
requirements in the 2007 to 2009 model years because there is not
sufficient lead time for manufacturers to develop a new monitor. The
new, more stringent monitoring requirements would begin in the 2010
model year, with a further tightening of the DPF NMHC threshold in the
2013 model year as is also proposed for over 14,000 pound applications.
4. NMHC Converting Catalyst Monitoring
We are proposing that the 8,500 to 14,000 pound NMHC converting
catalyst monitoring requirements mirror those discussed in section
II.B.5. Our current regulations do not require the monitoring of NMHC
catalysts on diesel applications. The proposed monitoring requirements
discussed in section II.B.5 would be far more comprehensive and
protective of the environment than the current lack of any requirement.
The required monitoring conditions with respect to performance tracking
(discussed in section II.B.8.c) would not apply for under 14,000 pound
heavy-duty applications since we do not have performance tracking
requirements for under 14,000 pound applications. We are not proposing
this new threshold for the 2007 to 2009 model years because there is
not sufficient lead time for manufacturers to develop a new monitor.
The new, more stringent monitoring requirements would begin in the 2010
model year, with a further tightening of the NMHC threshold in the 2013
model year as is also proposed for over 14,000 pound applications.
5. Other Monitors
We are also proposing changes to the emissions thresholds for all
other diesel monitors in the 8,500 to 14,000 pound range (e.g.,
NO_X sensors, air fuel ratio

[[Page 3255]]

sensors, etc.). These proposed changes are meant to maintain
consistency with the proposed changes for over 14,000 pound
applications. We believe that these proposed thresholds are far more
appropriate for diesel applications than the thresholds we have in our
current OBD requirements which are, generally, 1.5 times the applicable
standards. None of the proposed thresholds represents a new threshold
where none currently exists. Instead, they represent different
thresholds that would require, in most cases, malfunction detection at
different emissions levels than would be required by our current OBD
requirements.
6. CARB OBDII Compliance Option and Deficiencies
We are also proposing some changes to our deficiency provisions for
vehicles and engines meant for vehicles under 14,000 pounds. We have
included specific mention of air-fuel ratio sensors and NO_X
sensors where we had long referred only to oxygen sensors. We have also
updated the referenced CARB OBDII document that can be used to satisfy
the federal OBD requirements.\48\
---------------------------------------------------------------------------

\48\ See 13 CCR 1968.2, released August 11, 2006, Docket
ID# EPA-HQ-OAR-2005-0047-0005.
---------------------------------------------------------------------------

I. How Do the Proposed Requirements Compare to California's?

The California Air Resources Board (CARB) has its own OBD
regulations for engines used in vehicles over 14,000 pounds GVWR.\49\
(13 CCR 1971.1) In August of 2004, EPA and CARB signed a memorandum of
agreement to work together to develop a single, nationwide OBD program
for engines used in vehicles over 14,000 pounds.\50\ We believe that,
for the most part, we have been successful in doing so at least for the
early years of implementation. Nonetheless, there are differences in
some of the details contained within each regulation. These differences
are summarized here and we request comment on all of these differences.
---------------------------------------------------------------------------

\49\ 13 CCR 1971.1, Docket ID# EPA-HQ-OAR-2005-0047-0006.
\50\ ``Memorandum of Agreement: On-road Heavy-duty Diagnostic
Regulation Development,'' signed by Chet France, U.S. EPA, and Tom
Cackette, California ARB, August 11, 2004, Docket ID# EPA-
HQ-OAR-2005-0047-0002.
---------------------------------------------------------------------------

The first difference is that the CARB regulation contains some more
stringent thresholds beginning in the 2013 timeframe for some engines
and 2016 for all engines. Specifically, CARB's PM threshold for diesel
particulate filters (DPF) and exhaust gas sensors downstream of
aftertreatment devices, and their NO_X threshold for
NO_X aftertreatment devices and exhaust gas sensors
downstream of aftertreatment devices, become more stringent in 2013 for
some engines and 2016 for all. We are not proposing these more
stringent thresholds--our proposed thresholds are shown in Table II.B-
1. At this time, EPA is not in a position to propose these more
stringent OBD thresholds for the national program. The industry
believes that CARB's more stringent NO_X and PM thresholds
for 2013 and 2016 are not technically feasible. EPA is reviewing these
longer term OBD thresholds, but at this time we have not made a
decision regarding the feasibility and the appropriateness of these
longer term thresholds. Because these thresholds do not take effect
until model year 2013 at the earliest, we do not believe it is
necessary to make such a determination in this rulemaking. It would be
our intention to monitor the progress made towards complying with the
2010 thresholds contained in today's proposal and potentially revisit
the appropriateness of more stringent OBD thresholds for model year
2013 and later in the future. CARB has made commitments to review their
HD OBD program every two years and they can consider making changes to
their long-term program during this biennial review process. EPA's
regulatory development process does not lend itself to making updates
every two years because the Federal rulemaking process tends to be
lengthier than CARB's. As mentioned above, we intend to monitor the
CARB long-term thresholds during the coming years, and if we determine
that more stringent thresholds are appropriate, we would consider
changing our thresholds to include the more stringent thresholds
through a notice and comment rulemaking process.
CARB also has some slightly different certification demonstration
requirements in the 2011 and 2012 model years. They are requiring
demonstration testing of the child ratings from the 2010 model year
certified engine family for 2011 and 2012 model year certification. As
Table II.B-1 shows, we are not requiring such demonstration testing in
the 2011 and 2012 model years provided the child ratings meet the
requirements of certification carry-over. Further, CARB is requiring
that one engine rating from one to three engine families undergo full
certification demonstration testing in the 2013 model year and every
model year thereafter. In contrast, EPA is requiring that one to three
engine ratings be fully demonstrated in the 2013 model year and then
carry-over through the 2015 model year (again, provided the engine
ratings meet the requirements of certification carry-over). In 2016 and
subsequent model years, EPA would require that one to three engine
ratings be fully demonstrated on an ``as needed'' basis. In the same
vein, our evaluation protocol associated with certification
demonstration testing, as discussed in section VIII.C, requires less
testing than is required in CARB's regulation.
Our OBD requirements for over 14,000 pounds do not contain any
provisions to monitor control strategies associated with idle emission
control strategies because EPA does not have currently any regulatory
requirements that specifically target idle emissions control
strategies.\51\ We are not proposing a provision to charge fees
associated with OBD deficiencies as CARB does. We are also not
proposing provisions for ``retroactive deficiencies'' as CARB has. Our
deficiency provisions along with our misbuild and other in-use
enforcement programs accomplish the same thing. Deficiencies are
discussed in section VIII.D.\52\
---------------------------------------------------------------------------

\51\ Note that, by idle emission control strategies we mean
strategies that, for example, shut down the engine after 10 minutes
of constant idle. We do not mean strategies that control emissions
during engine idles that occur at stop lights or in congested traffic.
\52\ See also proposed Sec. 86.010-18(n).
---------------------------------------------------------------------------

For diesel engines used in heavy-duty vehicles under 14,000 pounds,
our proposed OBD requirements are in line with those recently proposed
by CARB.\53\ Our proposed requirements are also in line--both the
technical aspects and the implementation timing aspects--with our
proposed requirements for over 14,000 pound diesel applications. We are
also proposing diesel vehicle-based OBD requirements in line with the
proposed diesel engine-based requirements. In contrast, CARB does not
have diesel thresholds in terms of ``grams per mile'' specified in
their regulation for the 8,500 to 14,000 pound range.
---------------------------------------------------------------------------

\53\ See 13 CCR 1968.2, released August 11, 2006, Docket
ID# EPA-HQ-OAR-2005-0047-0005.
---------------------------------------------------------------------------

Specifically for gasoline engines meant for applications over
14,000 pounds, our proposal differs from CARB's in that we are not
requiring detection of catalysts that are less than 50 percent
effective at converting emissions.\54\ We are not requiring this
because we are relying on the emissions threshold of 1.75 times the
applicable standard as a means of defining a catalyst system
malfunction. We are also proposing some differences with respect to misfire
monitoring. Most notably, we are not proposing a provision analogous

[[Page 3256]]

to CARB's provision that allows the Executive Officer to approve
misfire monitor disablement or alternative malfunction criteria on a
case by case basis.\55\ In general, we prefer to avoid having
regulatory provisions that are implemented on a case by case basis. For
similar reasons, we are also not proposing a provision analogous to
CARB's provision that allows the Executive Officer to revise the
orifice for evaporative leak detection if the most reliable monitoring
strategy cannot detect the required orifice.\56\
---------------------------------------------------------------------------

\54\ See 13 CCR 1971.1(f)(6.2.1)(B) and compare to proposed
Sec. 86.010-18(h)(6)(ii).
\55\ See 13 CCR 1971.1(f)(2.3.4)(D) and compare to proposed
Sec. 86.010-18(h)(2)(iii)(D).
\56\ See 13 CCR 1971.1(f)(7.2.3) and compare to proposed Sec.
86.010-18(h)(7)(ii)(B) and (C).
---------------------------------------------------------------------------

III. Are the Proposed Monitoring Requirements Feasible?

Some of the OBD monitoring strategies discussed here would be
intrusive monitors that would result in very brief emissions increases,
or spikes, for the sake of determining if certain emissions control
components/systems are working properly during the remaining 99 percent
or more of the engine's operation. While these emissions spikes are
brief, and their levels cannot be meaningfully predicted or estimated,
we are concerned about strategies that might give little concern to
emissions during such spikes in favor of an easier monitor. We request
comment on this issue--should such strategies be allowed or should such
strategies be prohibited? If a commenter has the latter opinion, then
suggestions should be provided for how the monitoring requirements
should be changed to allow for a non-intrusive monitor--i.e., one that
could run during normal operation or operation ``on the cycle''--that
may not provide the monitoring capability nor the control expected by
the requirements we are proposing.

A. Feasibility of the Monitoring Requirements for Diesel/Compression-
Ignition Engines

1. Fuel System Monitoring
a. Fuel Pressure Monitoring
Manufacturers control fuel pressure by using a closed-loop feedback
algorithm that allows them to increase or decrease fuel pressure until
the fuel pressure sensor indicates they have achieved the desired fuel
pressure. For the common-rail OBD systems certified in the under 14,000
pound category, the manufacturers are monitoring the actual fuel system
pressure sensed by a fuel rail pressure sensor, comparing it to the
target fuel system pressure stored in a software table or calculated by
an algorithm inside the onboard computer, and indicating a malfunction
if the magnitude of the difference between these two exceeds an
acceptable level. The error limits are established by engine
dynamometer emission tests to ensure that a malfunction would be
detected before emissions exceed the applicable thresholds.
In cases where no fuel pressure error can generate a large enough
emission increase to exceed the applicable thresholds, manufacturers
are required to set the malfunction trigger at their fuel pressure
control limits (e.g., when they reach a point where they can no longer
increase or decrease fuel pressure to achieve the desired fuel
pressure). This monitoring requirement has been demonstrated as
technically feasible given that several under 14,000 pound diesels
already meet this requirement. Further, the nature of a closed-loop
algorithm is that such a system is inherently capable of being
monitored because it simply requires analysis of the same closed-loop
feedback parameter being used by the system for control purposes.
Another promising technology is a pressure sensing glow plug. The
glow plug is an electronic device in the cylinder of most diesel
engines used to facilitate combustion during cold engine starting
conditions. Glow plugs are being developed that incorporate a pressure
sensor capable of detecting the quality of combustion within the
cylinder.\57\ Pressure-sensing glow plugs provide feedback to the
engine-management system that controls the timing and quantity of fuel
injected into the cylinder. This feedback allows the engine electronics
to adjust the injection characteristics so the engine avoids fuel-
mixture combinations that generate high levels of NO_X. In
this sense, a feedback loop is available that works like the oxygen
sensor in a gasoline engine exhaust system. By measuring the quality of
combustion, a determination can also be made about the quality of the
fuel injection event--the pressure of fuel delivered, quantity of fuel
delivered, timing of fuel delivered.
---------------------------------------------------------------------------

\57\ ``Spotlight on Technology: Smart glowplugs may make Clean
Diesels cost-effective Pressure-sensing units could let designers
cut NO_X aftertreatment,'' Tony Lewin, Automotive News,
February 6, 2006.
---------------------------------------------------------------------------

b. Fuel Injection Quantity Monitoring
Absent combustion sensors and/or pressure sensing glow plugs
mentioned above, there is currently no feedback sensor indicating that
the proper quantity of fuel has been injected. Therefore, injection
quantity monitoring will be more difficult than pressure monitoring.
Nonetheless, a manufacturer has identified a strategy currently being
used that verifies the injection quantity under very specific engine
operating conditions and appears to be capable of determining that the
system is accurately delivering the desired fuel quantity. This
strategy entails intrusive operation of the fuel injection system
during a deceleration event where fuel injection is normally shut off
(e.g., coasting or braking from a higher vehicle speed down to a low
speed or a stop). During the deceleration, fuel injection to a single
cylinder is turned back on to deliver a very small amount of fuel.
Typically, the amount of fuel would be smaller than, or perhaps
comparable to, the amount of fuel injected during a pilot or pre-
injection. If the fuel injection system is working correctly, that
known injected fuel quantity will generate a known increase in
fluctuations (accelerations) of the crankshaft that can be measured by
the crankshaft position sensor. If too little fuel is delivered, the
measured crankshaft acceleration will be smaller than expected. If too
much fuel is delivered, the measured crankshaft acceleration will be
larger than expected. This process can even be used to ``balance'' out
each cylinder or correct for system tolerances or deterioration by
modifying the commanded injection quantity until it produces the
desired crankshaft acceleration and applying a correction or adaptive
term to that cylinder's future injections. Each cylinder can, in turn,
be cycled through this process and a separate analysis can be made for
the performance of the fuel injection system for each cylinder. Even if
this procedure would require only one cylinder be tested per revolution
(to eliminate any change in engine operation or output that would be
noticeable to the driver) and require each cylinder to be tested on
four separate revolutions, this process would only take two seconds for
a six cylinder engine decelerating through 1500 rpm.
The crankshaft position sensor is commonly used to identify the
precise position of the piston relative to the intake and exhaust
valves to allow for very accurate fuel injection timing control and, as
such, there exists sufficient resolution and data sampling within the
onboard computer to enable such measurement of crankshaft
accelerations. Further, in addition to the current use of this strategy
in an under 14,000 pound diesel application, a nearly identical
crankshaft fluctuation technique has been used since 1997 on under
14,000 pound diesel engines

[[Page 3257]]

during idle conditions to determine if individual cylinders are misfiring.
Another technique that may be used to achieve the same monitoring
capability is some variation on the current cylinder balance tests used
by many manufacturers to improve idle quality. In such strategies,
fueling to individual cylinders is increased, decreased, or shut off to
determine if the cylinder is contributing an equal share to the output
of the engine. This strategy again relies on changes in crankshaft/
engine speed to measure the individual cylinder's contribution relative
to known good values and/or the other cylinders. Such an approach seems
viable to determine whether the fuel injection quantity is correct for
each cylinder, but it has the disadvantage of not necessarily being
able to verify whether the system is able to deliver small amounts of
fuel precisely (such as those commanded during a pilot injection).
One other approach that has been mentioned but not investigated
thoroughly is the use of a wide-range air-fuel (A/F) sensor in the
exhaust to confirm fuel injection quantity. The A/F sensor output could
be compared to the measured air going into the engine and calculated
fuel quantity injected to see if the two agree. Differences in the
comparison may allow for the identification of incorrect fuel injection
quantity.
c. Fuel Injection Timing Monitoring
In the same manner as described for quantity monitoring, we believe
that fuel injection timing could be verified. By monitoring the
crankshaft speed fluctuation and, most notably, the time at which such
fluctuation begins, ends, or reaches a peak, the OBD system could
compare the time to the commanded fuel injection timing point and
verify that the crankcase fluctuation occurred within an acceptable
time delay relative to the commanded fuel injection. If the system was
working improperly and actual fuel injection was delayed relative to
when it was commanded, the corresponding crankshaft speed fluctuation
would also be delayed and would result in a longer than acceptable time
period between commanded fuel injection timing and crankshaft speed
fluctuation. A more detailed discussion of this possible monitoring
method is presented in the technical support document contained in the
docket.\58\
---------------------------------------------------------------------------

\58\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID# EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

Another possible monitoring method that has been mentioned but not
investigated thoroughly would be to look for an electrical feedback
signal from the injector to the computer to confirm when the injection
occurred. Such a technique would likely use an inductive signature to
identify exactly when an injector opened or closed and verify that it
was at the expected timing. We expect that further investigation would
be needed to confirm that such a monitoring technique would be
sufficient to verify fuel injection timing.
d. Fuel System Feedback Control Monitoring
The conditions necessary for feedback control (i.e., the feedback
enable criteria) are defined as part of the control strategy in the
engine computer. The feedback enable criteria are typically based on
minimum conditions necessary for reliable and stable feedback control.
When the manufacturer is designing and calibrating the OBD system, the
manufacturer would determine, for the range of in-use operating
conditions, the time needed to satisfy these feedback enable criteria
on a properly functioning engine. In-use, the OBD system would evaluate
the time needed for these conditions to be satisfied following an
engine start, compare that to normal behavior for the system, and
indicate a malfunction when the time exceeds a specified value (i.e.,
the malfunction criterion). For example, fuel pressure feedback control
may be calibrated to begin once fuel system pressure has reached a
minimum specified value. In a properly functioning system, pressure
builds in the system during engine cranking and shortly after starting
and the pressure enable criterion are reached within a few seconds.
However, in a malfunctioning system (e.g., due to a faulty low-pressure
fuel pump), it may take a significantly longer time to reach the
feedback enable pressure. A malfunction would be indicated when the
actual time to reach feedback enable pressure exceeds the malfunction
criterion.
Malfunctions that cause open-loop or default operation can be
readily detected as well. As discussed above, the feedback enable
criteria are clearly defined in the computer and are based on what is
necessary for reliable control. After feedback control has begun, the
OBD system can detect these criteria and indicate a malfunction when
they are no longer being satisfied. For example, one enable criterion
could be a pressure sensor reading within a certain range where the
upper pressure limit would be based on the maximum pressure that could
be generated in a properly functioning system. A malfunction would be
indicated if the pressure sensor reading exceeded the upper limit which
would cause the fuel system to go open loop.
The feedback control system adjusts the base fuel strategy such
that actual engine operating characteristics meet driver demand. But,
the feedback control system has limits on how much adjustment can be
made based, presumably, on the ability to maintain acceptable control.
Like the feedback enable criteria, these control limits are defined in
the computer. The OBD system would track the actual adjustments made by
the control system and continuously compare them with the control
limits. A malfunction would be indicated if the limits were reached.
2. Engine Misfire Monitoring
Diesel engines certified to the under 14,000 pound OBD requirements
have been monitoring for misfire since the 1998 model year. The
monitoring requirements we are proposing for over 14,000 pound
applications are identical to the existing requirements for under
14,000 pound applications for those engines that do not use combustion
sensors.\59\ Therefore, technological feasibility has been demonstrated
for these applications.
---------------------------------------------------------------------------

\59\ Technically, the EPA OBD diesel misfire monitoring
requirement for under 14,000 pound applications is to detect a lack
of combustion whereas the California OBDII diesel misfire monitoring
requirement is identical to what we are proposing for over 14,000
pounds. Since all manufacturers to date are designing to the OBDII
requirements, this statement is, for practical purposes, true.
---------------------------------------------------------------------------

For engines that use combustion sensors, the misfire monitoring
requirements are more stringent since the requirement calls for
detection of malfunctions causing emissions to exceed the emissions
thresholds. Nonetheless, detection on these engines should be straight
forward since the combustion sensors would provide a direct measurement
of combustion. Therefore, lack of combustion (i.e., misfire) could be
measured directly. The combustion sensors are intended to measure
various characteristics of a combustion event for feedback control.
Such feedback is needed for engines that require very precise air and
fuel metering controls such as would be required for homogeneous charge
compression ignition (HCCI) engine. Accordingly, the resolution of
sensors having that capability is well beyond what would be needed to
detect a complete lack of combustion.

[[Page 3258]]

3. Exhaust Gas Recirculation (EGR) Monitoring
a. EGR Low Flow/High Flow Monitoring
Typically, the EGR control system determines a desired EGR flow
rate based on the engine operating conditions such as engine speed and
engine load. The desired EGR flow rates, and the corresponding EGR
valve positions needed to achieve the desired flow rates, are
established when the manufacturer designs and calibrates the EGR
system. Once established, manufacturers store the desired EGR flow
rate/valve position in a lookup table in the onboard computer. During
operation, the onboard computer commands the EGR valve to the position
necessary to achieve the desired flow--i.e., the commanded EGR flow.
The onboard computer then calculates or directly measures both the
fresh air charge (fresh air intake) and total intake charge. The
difference between the total intake charge and fresh air intake is the
actual EGR flow. The closed-loop control system continuously adjusts the
EGR valve position until the actual EGR flow equals the desired EGR flow.
Such closed-loop control strategies and their associated OBD
monitoring strategies are used on many existing gasoline and diesel
vehicles under 14,000 pounds. The OBD system evaluates the difference
(i.e., error) between the look-up value--i.e., the desired flow rate--
and the final commanded value needed to achieve the desired flow rate.
Typically, as the feedback parameter or learned offset increases, there
is an attendant increase in emissions. A correlation can be made
between feedback adjustment and emissions. When the error exceeds a
specific threshold, a malfunction would be indicated. This type of
monitoring strategy could be used to detect both high and low flow
malfunctions.
While the closed-loop control strategy described above is effective
in measuring and controlling EGR flow, some manufacturers are currently
investigating the use of a second control loop based on an air-fuel
ratio (A/F) sensor (also known as wide-range oxygen sensors or linear
oxygen sensors) to further improve EGR control and emissions. With this
second control loop, the desired air-fuel ratio is calculated based on
engine operating conditions (i.e., intake airflow, commanded EGR flow
and commanded fuel). The calculated air-fuel ratio is compared to the
air-fuel ratio from the A/F sensor and refinements can be made to the
EGR and airflow rates--i.e., the control can be ``trimmed''--to achieve
the desired rates. On systems that use the second control loop, flow
rate malfunctions could also be detected using the feedback information
from the A/F sensor and by applying a similar monitoring strategy as
discussed above for the primary EGR control loop.
We are also proposing that two leaking EGR valve failure modes be
detected. One type is the failure of the valve to seal when in the
closed position. For example, if the valve or seating surface is
eroded, the valve could close and seat, yet still allow some flow
across the valve. A flow check is necessary to detect a malfunctioning
valve that closes properly but still leaks. EGR flow--total intake
charge minus fresh air charge--could be calculated using the monitoring
strategy described above for high and low flow malfunctions. With the
valve closed, a malfunction would be indicated when flow exceeds
unacceptable levels. Or, some cooled EGR systems will incorporate an
EGR temperature sensor that could be used to detect a leaking EGR valve
by reacting to the presence of hot exhaust gases when none should be
present. A leaking valve can also be caused by failure of the valve to
close/seat. For example, carbon deposits on the valve or seat could
prevent the valve from closing fully. The flow check described above
could detect failure of the valve to close/seat, but this approach
would require a repair technician to further diagnose whether the
problem is a sealing or seating problem. Such a failure of the valve to
close/seat could be more specifically monitored by closing the valve
and checking the zero position of the valve with a position sensor. If
the valve position is out of the acceptable range for a closed valve, a
malfunction would be indicated. This type of zero position sensor check
is commonly used to verify the closed position of valves/actuators used
in gasoline OBD systems (e.g. gasoline EGR valves, electronic throttle)
and should be feasible for diesel EGR valves.
b. EGR Slow Response Monitoring
While the flow rate monitor discussed above would evaluate the
ability of the EGR system to achieve a commanded flow rate under
relatively steady state conditions, the EGR slow response monitor would
evaluate the ability of the EGR system to modulate (i.e., increase and
decrease) EGR flow as engine operating conditions and, consequently,
commanded EGR rates change. Specifically, as engine operating
conditions and commanded EGR flow rates change, the monitor would
evaluate the time it takes for the EGR control system to achieve the
commanded change in EGR flow. This monitor could evaluate EGR response
passively during transient engine operating conditions encountered
during in-use operation. The monitor could also evaluate EGR response
intrusively by commanding a change in EGR flow under a steady state
engine operating condition and measuring the time it takes to achieve
the new EGR flow rate. Similar passive and intrusive strategies have
been developed for variable valve control and/or timing (VVT)
monitoring on vehicles under 14,000 pounds.
c. EGR Feedback Control Monitoring
Monitoring of EGR feedback control could be performed using
analogous strategies to those discussed in Section III.A.1 for
monitoring of fuel system feedback control.
d. EGR Cooling System Monitoring
Some diesel engine manufacturers currently use exhaust gas
temperature sensors as an input to their EGR control systems. On such
systems--EGR temperature--which is measured downstream of the EGR
cooler--could be used to monitor the effectiveness of the EGR cooler.
For a given engine operating condition (e.g., a steady speed/load that
generates a known exhaust mass flow and exhaust temperature to the EGR
cooler), EGR temperature will increase as the performance of the EGR
cooling system decreases. During the OBD calibration process,
manufacturers could develop a correlation between increased EGR
temperatures and cooling system performance (i.e., increased
emissions). The EGR cooling system monitor would use such a correlation
and indicate a malfunction when the EGR temperature increases to the
level that would cause emissions to exceed the emissions thresholds.
While we anticipate that most, if not all, manufacturers will use
EGR temperature sensors to meet future emissions standards, EGR cooling
system monitoring may be feasible without such a temperature sensor.
The monitor could be done using the intake manifold temperature (IMT)
sensor by looking at the change in IMT (i.e., ``delta'' IMT) with EGR
turned on and EGR turned off (IMT would be higher with EGR turned on).
If there is significant cooling capacity with a normally functioning
EGR cooling system, there would likely be a significant difference in
IMT with EGR turned on versus turned off. Delta IMT could be correlated
to decreased EGR cooling system performance and increased emissions.

[[Page 3259]]

4. Turbo Boost Control System Monitoring
a. Turbo Underboost/Overboost Monitoring
To monitor boost control systems, manufacturers are expected to
look at the difference between the actual pressure sensor reading (or
calculation thereof) and the desired/target boost pressure. If the
error between the two is too large or persists for too long, a
malfunction would be indicated. Manufacturers would need to calibrate
the size of error and/or error duration to ensure robust malfunction
detection occurs before the emissions thresholds are exceeded. Given
that the purpose of a closed-loop control system with a feedback sensor
is to measure continuously the difference between actual and desired
boost pressure, the control system is already monitoring that
difference and attempting to minimize it. As such, a monitoring
requirement to indicate a malfunction when the difference gets large
enough such that it can no longer achieve the desired boost is
essentially an extension of the existing control strategy.
To monitor for malfunction or deterioration of the boost pressure
sensors, manufacturers could validate sensor readings against other
sensors present on the vehicle or against ambient conditions. For
example, at initial key-on before the engine is running, the boost
pressure sensor should read ambient pressure. If the vehicle is
equipped with a barometric pressure sensor, the two sensors could be
compared and a malfunction indicated when the two readings differ
beyond the specific tolerances. A more crude rationality check of the
boost pressure sensor could be accomplished by verifying that the
pressure reading is within reasonable atmospheric limits for the
conditions the vehicle will be subjected to.
b. VGT Slow Response Monitoring
The VGT slow response monitor would evaluate the ability of the VGT
system to modulate (i.e., increase and decrease) boost pressure as
engine operating conditions and, consequently, commanded boost pressure
changes. Specifically, as engine operating conditions and commanded
boost pressures change, the monitor would evaluate the time it takes
for the VGT control system to achieve the commanded change in boost
pressure. This monitor could evaluate VGT response passively during
transient engine operating conditions encountered during in-use
operation. The monitor could also evaluate VGT response intrusively by
commanding a change in boost pressure under a steady state engine
operating condition and measuring the time it takes to achieve the new
boost pressure.
Rationality monitoring of VGT position sensors could be
accomplished by comparing the measured sensor value to expected values
for the given engine speed and load conditions. For example, at high
engine speeds and loads, the position sensor should indicate that the
VGT position is opened more than would be expected at low engine speeds
and loads. Such rationality checks would need to be two-sided (i.e.,
position sensors should be checked for appropriate readings at both
high and low engine speed/load operating conditions.
c. Turbo Boost Feedback Control Monitoring
Monitoring of boost pressure feedback control could be performed
using analogous strategies to those discussed for fuel system feedback
control monitoring in Section III.A.1.
d. Charge Air Undercooling Monitoring
We expect that most engines will make use of a temperature sensor
downstream of the charge air cooler to protect against overcooling
conditions that could cause excessive condensation, and to prevent
undercooling that could result in loss of performance. A comparison of
the actual charge air temperature to the expected, or design,
temperature would indicate any errors that might be occurring.
Manufacturers could correlate that error to an emissions impact and,
when the error reached a level such that emissions would exceed the
emissions thresholds, a malfunction would be indicated.
5. Non-Methane Hydrocarbon (NMHC) Converting Catalyst Monitoring
a. NMHC Converting Catalyst Conversion Efficiency Monitoring
Monitoring of the NMHC converting catalyst, or diesel oxidation
catalyst (DOC), could be performed similar to three-way catalyst
monitoring on gasoline engines. Three-way catalyst monitoring uses the
concept that catalyst's oxygen storage capacity correlates well with
its hydrocarbon conversion efficiency. Oxygen sensors located upstream
and downstream of the catalyst can be used to determine when its oxygen
storage capacity--and, hence, its conversion efficiency--has
deteriorated below a predetermined level.
Determining the oxygen storage capacity would require lean air-fuel
(A/F) operation followed by rich A/F operation or vice-versa during the
catalyst monitoring event. Since a diesel engine normally operates lean
of stoichiometry, lean A/F operation would be normal operation.
However, rich A/F operation would have to be commanded intrusively when
the catalyst monitor is active. The rich A/F operation could be
achieved by injecting some fuel late enough in the four stroke process
(i.e., late injection) that the raw fuel would not combust in-cylinder.
Rich A/F operation could also be achieved using an in-exhaust fuel
injector upstream of the catalyst. During normal lean operation, the
catalyst would become saturated with stored oxygen. As a result, both
the front and rear oxygen sensors should be reading lean. When rich A/F
operation initiates, the front oxygen sensor would switch immediately
to a ``rich'' indication. For a short time, the rear oxygen sensor
should continue to read ``lean'' until such time as the stored oxygen
in the catalyst is consumed by the rich fuel mixture in the exhaust and
the rear oxygen sensor would read ``rich.'' As the catalyst
deteriorates, the delay time between the front and rear oxygen sensors
switching from their normal lean state to a rich state would become
progressively smaller because the deteriorated catalyst would have less
oxygen storage capacity. Thus, by comparing the time difference between
the responses of the front and rear oxygen sensors to the lean-to-rich
or rich-to-lean A/F changes, the performance of the catalyst could be
estimated. Although this discussion suggests the use of conventional
oxygen sensors, these sensors could be substituted with A/F sensors
which would also provide for additional engine control benefits such as
EGR trimming and fuel trimming.
If a malfunction of the catalyst cannot cause emissions to exceed
the emissions thresholds, then only a functional monitor would be
required. A functional monitor could be done using temperature sensors.
A functioning oxidation catalyst would be expected to provide some
level of exotherm when it oxidizes HC and CO. The temperature of the
catalyst could be measured by placing one or more temperature sensors
at or near the catalyst. However, depending on the nominal conversion
efficiency of the catalyst and the duty cycle of the vehicle, the
exotherm may be difficult to discern from the inlet exhaust
temperatures. To add robustness to the monitor, the functional monitor
would need to be conducted during predetermined

[[Page 3260]]

operating conditions where the amount of HC and CO entering the
catalyst could be known. This may require an intrusive monitor that
actively forces the fueling strategy richer (e.g., through late or post
injection) than normal for a short period of time. If the measured
exotherm does not exceed a predetermined amount that only a properly-
working catalyst could achieve, a malfunction would be indicated. As
noted, such an approach would require a brief period of commanded rich
operation that would result in a very brief HC and perhaps a PM
emissions spike.
b. Other Aftertreatment Assistance Function Monitoring
A functional monitor should be sufficient for monitoring the
oxidation catalyst's ability to fulfill aftertreatment assistance
functions such as generating an exotherm for DPF regeneration or
providing a proper feedgas for SCR or NO_X adsorbers. We
would expect that manufacturers would use the exotherm approach
mentioned above either to measure directly for the proper exotherm or
to correlate indirectly for the proper feedgas. For catalysts upstream
of a DPF, we expect that this monitoring would be conducted during an
active or forced regeneration event.\60\ For catalysts downstream of
the DPF, we expect that manufacturers would have to add fuel
intrusively (either in-exhaust or through in-cylinder post-injection)
to create a sufficient exotherm to distinguish malfunctioning from
properly operating catalysts.
---------------------------------------------------------------------------

\60\ An active or forced regeneration would be those
regeneration events that are initiated via a driver selectable
switch or activator and/or those initiated by computer software.
---------------------------------------------------------------------------

6. Selective Catalytic Reduction (SCR) and NO_X Conversion
Catalyst Monitoring
a. SCR and NO_X Catalyst Conversion Efficiency Monitoring
We would expect manufacturers to use NO_X sensors to
monitor a lean NO_X catalyst. NO_X sensors placed
upstream and downstream of the lean NO_X catalyst could be
used to determine directly the NO_X conversion efficiency.
Manufacturers could potentially use a single NO_X sensor
placed downstream of the catalyst to measure catalyst-out
NO_X emissions. This would have to be done within a tightly
controlled engine operation window where engine-out NO_X
emissions (i.e., NO_X emissions at the lean NO_X
catalyst inlet) performance is relatively stable and could be estimated
reliably. Within this engine operation window, catalyst-out
measurements could be compared to the expected engine-out
NO_X emissions and a catalyst conversion efficiency could be
calculated. Should the calculated conversion efficiency be insufficient
to maintain emissions below the emissions thresholds, a malfunctioning
or deteriorated lean NO_X catalyst would be indicated. If
both an upstream and downstream NO_X sensor are used for
monitoring, the upstream sensor could be used to improve the overall
effectiveness of the catalyst by precisely controlling the air-fuel
ratio in the exhaust to the levels where the catalyst is most
effective.
For monitoring the SCR catalyst, care must be taken to account for
the cross sensitivity of NO_X sensors to ammonia
(NH₃). Current NO_X sensor technology tends to
have such a cross-sensitivity to ammonia in that as much as 65 percent
of ammonia can be read as NO_X.\61\ However, urea SCR
feedback control studies have shown that the NH₃
interference signal is discernable from the NO_X signal and
can, in effect, allow the design of a better feedback control loop than
a NO_X sensor that doesn't have any NH₃ cross-
sensitivity. In one study, a signal conditioning method was developed
that resulted in a linear output for both NH₃ and
NO_X from the NO_X sensor downstream of the
catalyst.\62\ Monitoring of the catalyst can be done by using the same
NO_X sensors that are used for SCR control. When the SCR
catalyst is functioning properly, the upstream sensor should read
``high'' for high NO_X levels while the downstream sensor
should read ``low'' for low NO_X and low ammonia levels. With
a deteriorated SCR catalyst, the downstream sensor should read similar
or higher values as the upstream sensor (i.e., high NO_X and
high ammonia levels) since the NO_X reduction capability of
the catalyst has diminished. Therefore, a malfunctioning SCR catalyst
could be detected when the downstream sensor output is near to or
greater than the upstream sensor output. A similar monitoring approach
could be used if a manufacturer models upstream NO_X
emissions instead of using an upstream NO_X sensor. In this
case, the comparison would be made between the modeled upstream
NO_X value and the downstream sensor value.
---------------------------------------------------------------------------

\61\ Schaer, C.M., Onder, C.H., Geering, H.P., and Elsener, M.,
``Control of a Urea SCR Catalytic Converter System for a Mobile
Heavy-Duty Diesel Engine,'' SAE Paper 2003-01-0776 which may be
obtained from Society of Automotive Engineers International, 400
Commonwealth Dr., Warrendale, PA, 15096-0001.
\62\ Ibid.
---------------------------------------------------------------------------

Manufacturers have expressed concern over both the sensitivity and
the durability of NO_X sensors. They are concerned that
NO_X sensors will not have the necessary sensitivity to
detect NO_X at the low levels that will exist downstream of
the NO_X catalyst. They are also concerned that
NO_X sensors will not be durable enough to last the full
useful life of big diesel trucks. We have researched NO_X
sensors--the current state of development and future expectations--and
summarized our findings in the technical support document in the docket
for this rule.\63\ Some of our findings are summarized here.
---------------------------------------------------------------------------

\63\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID# EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

Regarding NO_X sensor sensitivity, we expect that 2010
and later model year engines will have average tailpipe NO_X
emissions in the 0 to 50 ppm range. Current NO_X sensors have
an accuracy of ±10 ppm in the 0 to 100 ppm range. This means
that current NO_X sensors should be able to detect
NO_X emissions that exceed the standard by two to three times
the 2010 limit.\64\ This should allow for compliance with our proposed
threshold which is effectively 2.5 times the 2010 limit. Further, we
expect that NO_X sensors in the 0 to 100 ppm range with
±5 ppm accuracy will be available by the middle of 2006.
Regarding durability, improvements are being made and a test program is
currently underway with the intent of aging several NO_X
sensors placed at various exhaust system locations out to 6,000 hours
(roughly equivalent to 360,000 miles). Results after 2,000 hours of
aging are promising and results after 4,000 hours of aging are
currently being analyzed.\65\
---------------------------------------------------------------------------

\64\ Ibid.
\65\ Ibid.
---------------------------------------------------------------------------

b. SCR and NO_X Catalyst Active/Intrusive Reductant Injection
System Monitoring
If an active catalyst system is used--i.e., one that relies on
injection of a reductant upstream of the catalyst to assist in
emissions conversion--manufacturers would be required to monitor the
mechanism for adding the fuel reductant. In the active catalyst system,
a temperature sensor is expected to be placed near or at the catalyst
to determine when the catalyst temperature is high enough to convert
emissions. Because NO_X catalyst systems, especially lean
NO_X catalyst systems, tend to have a narrow temperature
range where they are most effective, adding reductant when the catalyst
temperature is not sufficiently high would waste reductant. If fuel is

[[Page 3261]]

used as the reductant, this would adversely affect fuel economy without
a corresponding reduction in emissions levels. Therefore, a temperature
sensor is expected to be placed in the exhaust near or at the catalyst
to help determine when reductant injection should occur. This same
sensor could be used to determine if an exotherm resulted following
reductant injection. The lack of an exotherm would indicate a
malfunction of the reductant delivery system.
Alternatively, any NO_X sensors used to monitor
conversion efficiency could be used to determine if reductant injection
has occurred. NO_X sensors are also oxygen sensors so they
could be used to determine the air-fuel ratio in the exhaust stream
which would allow for verification of reductant injection into the
exhaust. Further, with a properly functioning injector, the downstream
NO_X sensor should see a change from high NO_X
levels to low NO_X levels. In contrast, a lack of reductant
injection would result in continuously high NO_X levels at
the downstream NO_X sensor. Therefore, a malfunctioning
injector could be indicated when the downstream NO_X sensor
continues to measure high NO_X after an injection event has
been commanded.
Reductant level monitoring could also be conducted by using the
existing NO_X sensors that are used for control purposes.
Specifically, the downstream NO_X sensor can be used to
determine if the reductant tank no longer has sufficient reductant
available. Similar to the fuel reductant injection functionality
monitor described above, when the reductant tank has a sufficient
reductant quantity and the injection system is working properly, the
downstream NO_X sensor should see a change from high
NO_X levels to low NO_X levels. If the
NO_X levels remain constant both before and after reductant
injection, then the reductant was not properly delivered and either the
injection system is malfunctioning or there is no longer sufficient
reductant available in the reductant tank. Alternatively, reductant
level monitoring could be conducted by using a dedicated ``float'' type
level sensor similar to the ones used in fuel tanks. Some manufacturers
may prefer using a dedicated reductant level sensor in the reductant
tank to inform the vehicle operator of current reductant levels via a
gauge on the instrument panel. If such a sensor is used by the
manufacturer for operator convenience, it could also be used to monitor
the reductant level in the tank.
Monitoring the reductant itself--whether it be the wrong reductant
or a poor quality reductant--could also be conducted using the
NO_X sensors used for control purposes. If an improper
reductant is injected, the NO_X catalyst system would not
function properly. Therefore, NO_X emissions downstream from
the catalyst would remain high both before and after injection. The
downstream NO_X sensor would see the high NO_X
levels after injection and a malfunction would be indicated. If the
reductant tank level sensor indicated sufficient levels for injection
and decreasing levels following injections (which would mean the
injection system was working), then the probable cause of the
malfunction would be the reductant itself. For urea SCR systems,
another possible means of monitoring the reductant itself would be to
use a urea quality sensor in the urea tank. First generation sensors
show promise at verifying that urea is indeed in the tank, rather than
water or some other fluid, and that the urea concentration is within
the needed range (i.e., not diluted with water or some other fluid).
The sensor could also be used in place of a urea level sensor. By 2010,
we would expect subsequent generation sensors to provide even better
capability.\66\
---------------------------------------------------------------------------

\66\ Crawford, John M., Mitsui Mining & Smelting Co., Ltd.,
presentation to EPA, October 2006, Docket ID# EPA-HQ-OAR-2005-0047-0007.
---------------------------------------------------------------------------

c. SCR and NO_X Catalyst Feedback Control Monitoring
Monitoring of feedback control could be performed using analogous
strategies to those discussed for fuel system feedback control
monitoring in Section III.A.1.
7. NO_X Adsorber Monitoring
a. NO_X Adsorber Capability Monitoring
We expect that either NO_X sensors or A/F sensors along
with a temperature sensor will be used to provide the feedback
necessary to control the NO_X adsorber system. These same
sensors could also be used to monitor the NO_X adsorber
system's capability. The use of NO_X sensors placed upstream
and downstream of the adsorber system would allow the system's
NO_X reduction performance to be continuously monitored. For
example, the upstream NO_X sensor on a properly functioning
adsorber system operating with lean fuel mixtures, will read high
NO_X levels while the downstream NO_X sensor should
read low NO_X levels. With a deteriorated NO_X
adsorber system, the upstream NO_X levels will continue to be
high while the downstream NO_X levels will also be high.
Therefore, a malfunction of the system can be detected by comparing the
NO_X levels measured by the downstream NO_X sensor
versus the upstream sensor.
The possibility exists that an upstream NO_X sensor will
not be used for NO_X adsorber control. Manufacturers may
choose to model engine-out NO_X levels--based on engine
operating parameters such as engine speed, fuel injection quantity and
timing, EGR flow rate--thereby eliminating the need for the upstream
NO_X sensor. In this case, we believe that monitoring of the
system could be conducted using A/F sensors in place of NO_X
sensors.\67\ During lean engine operation with a properly operating
NO_X adsorber system, both the upstream and downstream A/F
sensors would indicate lean mixtures. When the exhaust gas is
intrusively commanded rich to regenerate the NO_X adsorber,
the upstream A/F sensor would quickly indicate a rich mixture while the
downstream sensor should continue to see a lean mixture due to the
chemical reaction of the reducing agents with NO_X and oxygen
stored on the adsorber. Once all of the stored NO_X and
oxygen has been released, the reducing agents in the exhaust would
cause the downstream A/F sensor to indicate a rich reading. The more
NO_X that is stored in the adsorber, the longer the delay
between the rich indications from the upstream and downstream sensors.
Thus, the time differential between the rich indications from the
upstream and downstream A/F sensors is a gauge of the NO_X
storage capacity of the adsorber. This delay could be correlated to an
emissions increase and the monitor could be calibrated to indicate a
malfunction upon detecting an unacceptably short delay. In fact, Honda
currently uses a similar approach to monitor the NO_X
adsorber on a 2003 model year gasoline vehicle which demonstrates the
viability of the approach in a shorter lived application. We have
studied A/F sensors and their durability with respect to longer lived
diesel applications and our results are summarized in a report placed
in the docket to this rule.\68\
---------------------------------------------------------------------------

\67\ Ingram, G.A. and Surnilla, G., ``On-Line Estimation of
Sulfation Levels in a Lean NO_X Trap,'' SAE Paper 2002-01-
0731 may be obtained from Society of Automotive Engineers
International, 400 Commonwealth Dr., Warrendale, PA 15096-0001.
\68\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID# EPA-HQ-OAR-2005-0047-0008.

---------------------------------------------------------------------------

[[Page 3262]]

b. NO_X Adsorber Active/Intrusive Reductant Injection System
Monitoring
The injection system used to achieve NO_X regeneration of
the NO_X adsorber could also be monitored with A/F sensors.
When the control system injects extra fuel to achieve a rich mixture,
the upstream A/F sensor would respond to the change in fueling and
could measure directly whether or not the proper amount of fuel had
been injected. If manufacturers employ a NO_X adsorber system
design that uses only a single A/F sensor downstream of the adsorber,
that downstream sensor could be used to monitor the performance of the
injection system. As discussed above, the downstream sensor would
switch from a lean reading to a rich reading when the stored
NO_X has been completely released and reduced. If the sensor
switches too quickly after rich fueling is initiated, then either too
much fuel has been injected or the adsorber itself has poor storage
capability. Conversely, if the sensor takes too long to switch after
rich fueling is initiated, it may be an indication that the adsorber
has very good storage capability. However, excessive switch times
(i.e., times that exceed the maximum storage capability of the
adsorber) could be indicative of an injection system malfunction (i.e.,
insufficient fuel has been injected) or a sensor malfunction (i.e., the
sensor has a slow response).
c. NO_X Adsorber Feedback Control Monitoring
Monitoring of feedback control could be performed using analogous
strategies to those discussed for fuel system feedback control
monitoring in Section III.A.1.
8. Diesel Particulate Filter (DPF) Monitoring
a. PM Filtering Performance Monitoring
The PM filtering performance monitor is perhaps the monitor for
which we have the most concern with respect to feasibility. Part of
this concern stems from the difficulty in detecting the very low PM
emissions levels required for 2007/2010 engines (i.e., 0.01 g/bhp-hr).
While we have made changes to our test procedures that will allow for
more accurate measurement of PM in the test cell, it is still very
difficult to do. With today's proposal, we are expecting manufacturers
to detect failures in the filtering performance of only a few times the
actual standards. Success at doing so presents a very difficult
challenge to manufacturers. Our concerns, in part, have led us to
propose a different 2013 and later emissions threshold for this monitor
than that proposed by ARB. This was discussed in more detail in section
I.D.2.
We anticipate that manufacturers can meet the proposed PM filtering
monitor requirements without adding hardware other than that used for
control purposes. We believe that the same pressure and temperature
sensors that are used to control DPF regeneration will be used for OBD
monitoring. For control purposes, manufacturers generally use a
differential or delta pressure sensor placed across the DPF and at
least one temperature sensor located near the DPF. The differential
pressure sensor is expected to be used on DPF systems to prevent damage
that could be caused by delayed or incomplete regeneration. Such
conditions could lead to excessive temperatures and melting of the DPF
substrate. When the differential pressure exceeds a predetermined
level, a regeneration event would be initiated to burn the trapped PM.
However, engine manufacturers have told us that differential
pressure alone does not provide a robust indication of trapped PM in
the DPF. For example, most if not all DPFs in the 2010 timeframe will
be catalyzed DPFs that are designed to regenerate passively during most
operation. Sometimes, conditions will not permit the passive
regeneration and an active regeneration would have to be initiated.
Relying solely on the differential pressure sensor to determine when an
active regeneration event was necessary would not be sufficient. A low
differential pressure could mean a low PM load and could also mean a
leaking DPF substrate. A high differential pressure could mean a high
PM load and could also mean a melted substrate. In the latter case, the
system may continually attempt to regenerate the DPF despite a low PM
load which would both waste fuel and increase HC emissions.
As a result, manufacturers will probably use some sort of soot-
loading model to predict the PM load on the DPF as part of their
regeneration strategy. Without a robust prediction, a regeneration
event could be initiated too early (i.e., when too little PM was
present which would be a waste of fuel and would increase HC emissions)
or too late (i.e., when too much PM has been allowed to build and the
regeneration event could cause a meltdown of the substrate). The model
would estimate the PM load by tracking the difference between the
modeled engine-out PM (i.e., the emissions that are being loaded on the
DPF) and regenerated PM (i.e., the PM that is being burned off the DPF
due to passive and/or active regenerations).
Given this, we believe that a comprehensive and accurate soot-
loading model is also necessary for successful monitoring of DPF
filtering performance. The model would predict the PM load on the DPF
based on fuel consumption and engine operating conditions and would
predict passively regenerated PM based on temperatures. This predicted
PM load would be compared to the measured PM load taken from the
differential pressure sensors. Differences would correspond to either a
leaking substrate (i.e., predicted load greater than measured load) or
melting of the substrate faceplate (i.e., measured load greater than
predicted load).
Nonetheless, much development remains to be done and success is not
guaranteed. Manufacturers have noted that a melted substrate through
which a large channel has opened could have differential pressure
characteristics identical to a good substrate despite allowing most of
the engine-out PM to flow directly through. We agree that this is a
difficult failure mode and have proposed language that would allow
certification of DPF monitors that are unable to detect it. Possibly, a
temperature sensor in the DPF could detect the extreme temperatures
capable of causing such a severe substrate melting. Upon detecting such
a temperature, a regeneration event could be initiated to burn off any
trapped PM. Following that event, the soot model would expect a certain
increase in differential pressure based on modeled engine-out PM and
passive regeneration characteristics. Presumably, the measured
differential pressure profile would not match the predicted profile
because most PM would be flowing straight through the melted channel.
This same approach, or perhaps a simple temperature sensor, should
quite easily be able to detect a missing substrate.
Lastly, manufacturers have noted their concern that small
differences in substrate crack size or location may generate large
differences in tailpipe emission levels. They have also noted their
lack of confidence that they will be able to reliably detect all leaks
that would result in emissions exceeding the proposed thresholds.
Accordingly, the manufacturers have suggested pursuing an alternate
malfunction criterion independent of emission level. They have
suggested criteria such as a percent of exhaust flow leakage or a
specific leak or hole size that must be detected. We believe that
pursuit of such alternate thresholds would not be appropriate at this
time. Manufacturers have not yet completed work on initial widespread

[[Page 3263]]

implementation of DPFs for the 2007 model year. We expect that during
the year or two following that implementation, substantial refinement
and optimization will occur based on field experiences and that
correlation of sensor readings to emissions levels will be possible for
at least some DPF failure modes by the 2010 model year.
b. DPF Regeneration Monitoring
Pressure sensing, in combination with the soot model, could also be
used to determine if regeneration is functioning correctly. After a
regeneration event, the differential pressure should drop significantly
since the trapped PM has been removed. If it does not drop to within
the soot model's predicted range after the regeneration event, either
the regeneration did not function correctly or the filter could have
excessive ash loading. Ash loading is a normal byproduct of engine
operation (the ash loading is largely a function of oil consumption by
the engine and the ash content of the engine oil). The ash builds up in
the DPF and does not burnout as does the PM but rather must be removed
or blown out of the DPF. Manufacturers are working with us to determine
the necessary maintenance intervals at which this ash removal will
occur. The soot model would have to account for ash buildup in the DPF
with miles or hours of operation. Future engine oils will have lower
ash content and have tighter quality control such that more accurate
predictions of ash loading will be possible. By including ash loading
in the soot model, we believe that its effects could be accounted for
in the predicted differential pressure following a regeneration event.
As stated, manufacturers are projected to make use of temperature
sensors for regeneration control. These same sensors could also be used
to monitor active regeneration of the filter. If excess temperatures
are seen by the temperature sensor during active regeneration, the
regeneration process can be stopped or slowed down to protect the
filter. If an active regeneration event is initiated and there a
temperature rise commensurate with the amount of trapped PM is not
detected, the regeneration system is not working and a malfunction
would be indicated.
c. DPF NMHC Conversion Efficiency Monitoring
Given the stringency of the 2010 standards, we believe that
manufactures may rely somewhat on the DPF to convert some of the HC
emissions. The proposed requirement requires monitoring this function
only if the system serves this function. We believe that, provided the
filtering performance and regeneration system monitors have not
detected any malfunctions, the NMHC conversion is probably working
fine. Given the level of the threshold, and the expectation that the
DPF will serve to control NMHC only marginally, we do not anticipate
this monitor needing emissions correlation work. Instead, we expect
that, with the DPF temperature sensor, it should be possible to infer
adequate NMHC conversion by verifying an exotherm. Nonetheless, if a
manufacturer relies so heavily on the DPF for NMHC conversion that its
ability to convert could be compromised to the point of emissions
exceeding the threshold, a more robust monitor may be required by
correlating exotherm levels to NMHC impacts.
d. DPF Regeneration Feedback Control Monitoring
Monitoring of DPF regeneration feedback control could be performed
using analogous strategies to those discussed for fuel system feedback
control monitoring in Section III.A.1.
9. Exhaust Gas Sensor Monitoring
The under 14,000 pound OBD regulations have required oxygen sensor
monitoring since the 1996 model year. Vehicles have been certified
during that time meeting the requirements. The technological
feasibility of monitoring oxygen sensors has been demonstrated.
Additionally, A/F sensor monitoring has been required, manufacturers
have complied, and the feasibility has been similarly demonstrated.
NO_X sensors are a recent technology and, as such, they
are still being developed and improved. However, we would expect that
manufacturers would design their upstream NO_X sensor
monitors to be similar the A/F sensor monitors used in under 14,000
pound applications. Monitoring of downstream sensors may require
modifications to existing A/F sensor strategies and/or new strategies.
Since NO_X sensors are projected to be used only for control
and monitoring of aftertreatment systems that reduce NO_X
emissions (e.g., SCR systems), the OBD system would have to distinguish
between deterioration of the aftertreatment system and the
NO_X sensor itself. As the aftertreatment deteriorates,
NO_X emissions downstream of the aftertreatment device will
increase and, assuming there is no such deterioration in the
NO_X sensor, the NO_X sensor will read these
increasing NO_X levels. As discussed in sections III.A.6 and
III.A.7, the increased NO_X levels can be the basis for
monitoring the performance of the aftertreatment system. However, if
the NO_X sensor does deteriorate with the aftertreatment
device (i.e., its response rate slows with mileage/operating hours),
the sensor may not properly read the increasing NO_X levels
from the deteriorating aftertreatment system, and the aftertreatment
monitor might conclude that the aftertreatment system is functioning
properly. Similarly, the performance or level of deterioration of the
NO_X aftertreatment device could affect the results of the
NO_X sensor monitor. Therefore to achieve robust monitoring
of aftertreatment and sensors, the OBD system has to distinguish
between deterioration of the aftertreatment system and deterioration of
the NO_X sensor. To properly monitor the NO_X
sensor, the sensor monitor has to run under conditions where the
aftertreatment performance can be quantified and compensated for or
eliminated in the monitoring results.
For example, the effects of the SCR performance could be eliminated
by monitoring the NO_X sensor under a steady-state operating
condition during which engine-out NO_X emissions were stable.
Under a relatively steady-state condition, reductant injection could be
``frozen'' (i.e., the reductant injection quantity could be held
constant) which would also freeze the conversion efficiency of the SCR
system. With SCR performance held constant, engine-out NO_X
emissions could be intrusively increased by a known amount (e.g., by
reducing EGR flow or changing fuel injection timing and allowing the
engine-out NO_X model to determine the increase in
emissions). The resulting increase in emissions would pass through the
SCR catalyst unconverted, and the sensor response to the known increase
in NO_X concentrations could be measured and evaluated. This
strategy could be used to detect both response malfunctions (i.e., the
sensor reads the correct NO_X concentration levels but the
sensor reading does not change fast enough to keep up with changing
exhaust NO_X concentrations) and rationality malfunctions
(i.e., the sensor reads the wrong NO_X level). Rationality
malfunctions could be detected by making sure the sensor reading
changes by the same amount as the intrusive change in emissions.
Lastly, the sensor response to decreasing NO_X concentrations
could also be evaluated by measuring the response when the intrusive
strategy is turned off and engine-out NO_X emissions are
returned to normal levels. By correlating sensor response rates and the
resulting

[[Page 3264]]

emissions impacts, the malfunction criteria could then be determined.

B. Feasibility of the Monitoring Requirements for Gasoline/Spark-
Ignition Engines

1. Fuel System Monitoring
For gasoline vehicles since the 1996 model year and gasoline
engines since the 2005 model year, the under 14,000 pound OBD
requirements have required fuel system monitoring identical to that
being proposed. Over 100 million cars and light trucks have been built
and sold in the U.S. to these fuel system monitoring requirements
including some heavy-duty vehicles that use the exact same gasoline
engines that are used in some over 14,000 pound applications. This clearly
demonstrates the technological feasibility of the proposed requirements.
2. Engine Misfire Monitoring
For gasoline vehicles since the 1996 model year and gasoline
engines since the 2005 model year, the under 14,000 pound OBD
requirements have required misfire monitoring identical to that being
proposed. One of the most reliable methods for detecting misfire is the
use of a crankshaft position sensor--which measures the fluctuations in
engine angular velocity to determine the presence of misfire--along
with a camshaft position sensor--which can be used to identify the
misfiring cylinder. This method has been shown to be technologically
feasible and should work equally well on over 14,000 pound applications.
3. Exhaust Gas Recirculation (EGR) Monitoring
For vehicles since the 1996 model year and engines since the 2005
model year, the under 14,000 pound OBD requirements have required EGR
system monitoring identical to that being proposed. The general
approach has been to detect EGR flow rate malfunctions by looking at
the change in fuel trim or manifold pressure under conditions when the
EGR system is active. This demonstrates the technological feasibility
of the proposed requirements.
4. Cold Start Emission Reduction Strategy Monitoring
We expect this monitoring to be done mainly via computer software.
For example, if spark retard is used during cold starts, the commanded
amount of spark retard would have to be monitored if the amount of
spark retard can be restricted by external factors such as idle quality
or driveability. This can be done with software algorithms that compare
the actual overall commanded final ignition timing with the threshold
timing that would result in emissions that exceed the emissions
thresholds. Cold start strategies that always command a predetermined
amount of ignition retard independent of all other factors and do not
allow idle quality or other factors to override the desired ignition
retard would not require monitoring of the commanded timing. Other
methods that could be used to ensure that the actual timing has been
reached include verifying other factors such as corresponding increases
in mass air flow and idle speed indicative of retarded spark
combustion. Both mass air flow and idle speed are used currently by the
engine control system and the OBD system and, therefore, only minor
software modifications should be required to analyze these signals
while the cold start strategy is invoked.
5. Secondary Air System Monitoring
A/F sensors would most likely be required to monitor effectively
the secondary air system when it is normally active. These sensors are
currently installed on many new cars and their implementation is
projected to increase in the future as more stringent emission
standards are phased in. A/F sensors are useful in determining air-fuel
ratio over a broader range than conventional oxygen sensors and are
especially valuable in engines that require very precise fuel control.
They would be useful for secondary air system monitoring because of
their ability to determine air-fuel ratio with high accuracy. This
would enable a correlation between secondary airflow rates and emissions.
6. Catalytic Converter Monitoring
A common method used for estimating catalyst efficiency is to
measure the catalyst's oxygen storage capacity. This monitoring method
has been used by all light-duty gasoline vehicles since the 1996 model
year and most gasoline engines since the 2005 model year as a result of
our under 14,000 OBD requirements. Generally, as the catalyst's oxygen
storage capacity decreases, the conversion efficiencies of HC and
NO_X also decrease. With this strategy, a catalyst
malfunction would be detected when its oxygen storage capacity has
deteriorated to a predetermined level. Manufacturers determine this by
using the information from an upstream oxygen sensor and a downstream
or mid-bed oxygen sensor (this second sensor is also used for trimming
the front sensor to maintain more precise fuel control). By comparing
the level of oxygen measured by the second sensor with that measured by
the upstream sensor, manufacturers can determine the catalyst's oxygen
storage capacity and estimate its conversion efficiency. With a
properly functioning catalyst, the second oxygen sensor signal will be
fairly steady since the fluctuating oxygen concentration (due to fuel
system cycling around stoichiometry) at the inlet of the catalyst is
damped by the storage and release of oxygen in the catalyst. When a
catalyst is deteriorated it is no longer capable of storing and
releasing oxygen. This causes the frequency and peak-to-peak voltage of
the second oxygen sensor to simulate the signal from the upstream
oxygen sensor at which time a malfunction would be indicated.
7. Evaporative System Monitoring
Our OBD requirements have required monitoring for evaporative
system leaks for many years. The EPA OBD requirement has been the
equivalent of a 0.040 inch hole, while the ARB requirement has gone as
low as a 0.020 inch hole. These requirements have been met on
applications such as incomplete trucks and engine dynamometer certified
configurations equipped with similar and, in many cases, identical
configurations as are used in over 14,000 pound applications.
Manufacturers have successfully met these requirements by using engine
vacuum to create a vacuum in both the fuel tank and evaporative system
and then monitoring the system's ability to maintain that vacuum. The
ramp down in vacuum (or ramp up in pressure) can then be correlated to
leak size. In general, these systems require the addition of an
evaporative system pressure sensor and a canister vent valve capable of
closing the vent line.
Manufacturers of over 14,000 pound applications have expressed
concerns with their ability to detect evaporative system leaks on these
larger vehicles. One such concern relates to the relatively larger fuel
tank sizes on the larger applications. These tanks can be on the order
of 50 to 80 gallons, which makes the impact of a small hole, on a
percentage basis, less severe and less easily detected. Another concern
is the relatively large number of fuel tank and evaporative system
configurations on the larger applications. Confounding both of these
concerns is that the engine manufacturers quite often have no idea what
tanks and configurations will ultimately be matched with their engine
in the final vehicle product.
While we agree that these concerns are valid, they can also be said
of the

[[Page 3265]]

under 14,000 pound applications (except perhaps the tank size concern).
The over 14,000 pound gasoline applications are expected to use near
identical, if not equivalent, evaporative system components and we are
not aware of any reason why the existing monitoring techniques would
not continue to work on over 14,000 pound applications. Nonetheless, we
do not want false failures in the field. By limiting the monitoring
requirement to leaks of 0.150 inch or larger, we believe that
manufacturers would be able to employ a single monitoring strategy to
all possible tank sizes and configurations without much concern for
false failures. Nonetheless, it may be necessary for manufacturers to
impose tighter restrictions on their engine purchasers than is done
currently with regards to tank specifications and evaporative system
components.
8. Exhaust Gas Sensor Monitoring
Our light-duty OBD requirements since the 1996 model year and our
8,500 to 14,000 pound OBD requirements since the 2005 model year have
required oxygen sensor monitoring similar to the requirements being
proposed. Years of compliance with those requirements demonstrates the
technological feasibility of the proposed requirements. Additionally,
A/F sensor monitoring has been required and demonstrated on these
vehicles for many years.

C. Feasibility of the Monitoring Requirements for Other Diesel and
Gasoline Systems

1. Variable Valve Timing and/or Control (VVT) System Monitoring
VVT systems are already in general use in many under 14,000 pound
applications. Further, under the California OBD II requirements,
vehicles equipped with VVT systems have been monitoring those systems
for proper function since the 1996 model year. More recently,
manufacturers have employed monitoring strategies to detect VVT system
malfunctions that detect not only proper function but also exceedances
of emissions thresholds. Such strategies include the use of the crank
angle sensor and camshaft position sensor to confirm that the valve
opening and closing occurs within an allowable tolerance of the
commanded crank angle. By calculating the difference between the
commanded valve opening crank angle and the achieved valve opening
crank angle, a diagnostic algorithm can differentiate between a
malfunctioning system with too large of an error and a properly
functioning system with very little to no error. By calibrating the
size of this error (or integrating it over time), manufacturers can
design the system to indicate a malfunction prior to the required
emissions thresholds. In the same manner, system response can be
measured by monitoring the length of time necessary to achieve the
commanded valve timing. To ensure adequate resolution between properly
functioning systems and malfunctioning systems, most manufacturers
perform this type of monitor only when a sufficiently large ``step
change'' in commanded valve timing occurs.
2. Engine Cooling System Monitoring
The existing OBD requirements have required identical ECT sensor
and thermostat monitoring for several years. While the technical
feasibility of the proposed requirements has been demonstrated on
lighter applications which tend to be produced through a vertically
integrated manufacturing process, the manufacturers of big diesel
engines have expressed concerns that monitoring of the cooling system
on over 14,000 pound applications would create unique and possibly
insurmountable challenges. Generally, the cooling system is divided
into two cooling circuits connected by the thermostat. The two circuits
are the engine circuit and the radiator circuit. Since the big diesel
engine industry tends to be horizontally integrated, the manufacturers
contend that they do not know what types of devices will be added to
the cooling system when the vehicle is manufactured or the vehicle is
put into service. They are concerned that the unknown devices can add/
remove unknown quantities of heat to/from the system which would
prevent them from predicting reliably the proper system behavior (e.g.,
warm up). Without the ability to predict system behavior reliably, they
fear that they cannot know when the system is malfunctioning (e.g., not
warming up as expected).
The industry's concerns regarding unknown devices added on the
radiator circuit of the system seem unwarranted. A properly functioning
thermostat does not allow flow through the radiator during warm-up.
Devices added to the radiator circuit could only affect coolant
temperature when there is significant coolant flow through the radiator
(i.e., after the engine is warmed-up and the thermostat is open,
allowing coolant to flow through the radiator).
We agree that unknown devices added on the engine circuit (e.g.,
passenger compartment heaters) can affect the warm-up rate of the
system. Manufacturers of under 14,000 pound applications have
demonstrated robust thermostat monitoring with high capacity passenger
heaters in the cooling system. To do so, they have to know the maximum
rate of heat loss due to the heater. Manufacturers of over 14,000 pound
applications have control over this by providing limits on such devices
in the build specifications that they provide to the vehicle
manufacturers. In some cases, an engine manufacturer might need
multiple build specifications with corresponding thermostat monitoring
calibrations to accommodate the ranges of heater capacities that are
needed when a given engine is used in a range of vehicle applications
(e.g., a local delivery truck having a passenger compartment for two
people and a small capacity heater versus a bus having a passenger
compartment for 20 people and a large capacity heater). The vehicle
manufacturer would then select the appropriate calibration for the
engine when installing it in the vehicle. Nonetheless, engine
manufacturers have requested limited enable conditions for the
thermostat monitor (e.g., to disable the thermostat monitor below 50
degrees F). This would help to minimize their resource needs to
calibrate the thermostat monitor. While this may be directionally
favorable to manufacturers, it would result in disabled thermostat
monitoring during cold ambient conditions which occur in much of the
country and, in some areas, during a large portion of the year. In such
regions, a vehicle could experience a thermostat malfunction with no
indication to the vehicle operator. Since many other OBD monitors will
operate only after reaching a certain engine coolant temperature, a
malfunctioning thermostat without any indication could effectively
result in disablement of the OBD system.
3. Crankcase Ventilation System Monitoring
Crankcase ventilation system monitoring requirements have been met
for years by manufacturers of under 14,000 pound gasoline applications.
Therefore, the technological feasibility has been demonstrated for
gasoline applications.
Effectively, diesel engine manufacturers would be required to meet
design requirements for the entire system in lieu of actually
monitoring any of the hoses for disconnection. Specifically, the
proposed requirement would allow for an exemption for any portion of
the system that is resistant to deterioration or accidental
disconnection and not subject to disconnection during any of the

[[Page 3266]]

manufacturer's repair procedures for non-crankcase ventilation system
repair work. These safeguards would be expected to eliminate the
chances of disconnected or improperly connected hoses while still
allowing manufacturers to meet the requirements without adding any
additional hardware meant solely for the purpose of meeting the
monitoring requirements.
4. Comprehensive Component Monitoring
Both ARB and EPA OBD requirements have for year contained
requirements to monitor computer input and output components. While
these monitors are sometimes tricky and are not easy as many
incorrectly assume, the many years of successful implementation and
compliance with the existing requirements demonstrates their
feasibility. The proposed requirements are equivalent to the under
14,000 pound requirements.

IV. What Are the Service Information Availability Requirements?

A. What Is the Important Background Information for the Proposed
Service Information Provisions?

Section 202(m)(5) of the CAA directs EPA to promulgate regulations
requiring OEMs to provide to:

any person engaged in the repairing or servicing of motor vehicles
or motor vehicle engines, and the Administrator for use by any such
persons, * * * any and all information needed to make use of the
[vehicle's]
emission control diagnostic system * * * and such other
information including instructions for making emission-related
diagnoses and repairs.

Such requirements are subject to the requirements of section 208(c)
regarding protection of trade secrets; however, no such information may
be withheld under section 208(c) if that information is provided
(directly or indirectly) by the manufacturer to its franchised dealers
or other persons engaged in the repair, diagnosing or servicing of
motor vehicles.
On June 27, 2003 EPA published a final rulemaking (68 FR 38428)
which set forth the Agency's service information regulations for light-
and heavy-duty vehicles and engines below 14,000 pounds GVWR. These
regulations, in part, required each-covered Original Equipment
Manufacturer (OEM) to do the following: (1) OEMs must make full text
emissions-related service information available via the World Wide Web.
(2) OEMs must provide equipment and tool companies with information
that allows them to develop pass-through reprogramming tools. (3) OEMs
must make available enhanced diagnostic information to equipment and
tool manufacturers and to make available OEM-specific diagnostic tools
for sale. These requirements were finalized to ensure that aftermarket
service and repair facilities have access to the same emission-related
service information, in the same or similar manner, as that provided by
OEMs to their franchised dealerships.
As EPA moves forward proposing OBD requirements for the heavy-duty
over 14,000 pounds sector, EPA is similarly moving forward with
proposals to require the availability of service information to heavy-
duty aftermarket service providers as required by section 202(m) of the
Clean Air Act.
All of the following proposed provisions regarding the availability
of service information for the heavy-duty industry are based on our
extensive experience and regulatory history with the light-duty service
industry. However, as discussed below, EPA understands that there may
be significant differences between the light-duty service industry and
the heavy-duty service industry. EPA welcomes comment on all of the
proposed provisions and their need and/or applicability to the heavy-
duty service industry.
B. How Do the Below 14,000 Pound and Above 14,000 Pounds Aftermarket
Service Industry Compare?
As we consider proposing the availability of service information
for the heavy-duty sector above 14,000 pounds, EPA recognizes that
differences do exist between the industries that service vehicles above
and below 14,000 pounds. On the below 14,000 pound side, estimates
indicate that independent technicians perform up to 80% of all vehicle
service and repairs once a vehicle exceeds the manufacturer warranty
period.\69\ On the above 14,000 pound side, the 1997 U.S. Census Bureau
Vehicle Inventory and Use Survey, estimated that 25 percent of the
general maintenance and over 30 percent of the major overhaul on heavy-
duty vehicles was performed by the independent sector. According to the
Census Bureau, these values represent a 16.7 percent increase in
general maintenance and a 6.2 percent increase in major overhaul from
1992. Trucks and Parts Service Magazine provides the following
information on the breakdown of the independent repair industry for
vehicles above 14,000 pounds (not including any fuel injection shops):
---------------------------------------------------------------------------

\69\ Motor and Equipment Manufacturers Association, Automotive
Industry Status Report, 1999.

U.S. independent machine shops for above 14,000 pounds--5,820
U.S. independent engine service shops for above 14,000 pounds--12,170
U.S. independent transmission repair shops for above 14,000 pounds--11,420
Technicians, independent repair shops for above 14,000 pounds--133,700
Technicians, truck parts distributors for vehicles above 14,000
pounds--41,600

Thus, the increase in business and the large number of independent
aftermarket shops make it necessary that repair information is readily
available for the aftermarket trucking industry.
On the light-duty side, vehicle manufacturers are entirely
integrated in that they are responsible for the design and production
of the entire vehicle from the chassis to the body. In comparison, the
heavy-duty industry is mostly non-integrated. In other words, different
manufacturers separately produce the engine, the chassis, and the
transmission of a vehicle. This non-integration speaks to the fact that
a completed vehicle is typically produced in response to the customized
needs of owners/operators. In addition, the lack of integration
indicates that a given engine will ultimately be part of many different
engine, transmission, and chassis configurations. In addition, heavy-
duty manufacturers have stated that diagnostic tool designs differ
significantly from tools produced for light-duty vehicles as a result
of this non-integration.
EPA requests comment and also additional data on the current state
of the heavy-duty aftermarket industry.

C. What Provisions Are Being Proposed for Service Information Availability?

1. What Information Is Proposed To Be Made Available by OEMs?
Today's action proposes a provision that requires OEMs to make
available to any person engaged in the repairing or servicing of heavy-
duty motor vehicles or motor vehicle engines above 14,000 pounds all
information necessary to make use of the OBD systems and any
information for making emission-related repairs, including any
emissions-related information that is provided by the OEM to franchised
dealers beginning with MY2010. We are proposing that this information
includes, but is not limited to, the following:
(1) Manuals, technical service bulletins (TSBs), diagrams, and
charts (the provisions for training materials,

[[Page 3267]]

including videos and other media are discussed in Sections II.C.3 and
II.C.4 below.
(2) A general description of the operation of each monitor,
including a description of the parameter that is being monitored.
(3) A listing of all typical OBD diagnostic trouble codes
associated with each monitor.
(4) A description of the typical enabling conditions for each
monitor to execute during vehicle operation, including, but not limited
to, minimum and maximum intake air and engine coolant temperature,
vehicle speed range, and time after engine startup. A listing and
description of all existing monitor-specific drive cycle information
for those vehicles that perform misfire, fuel system, and comprehensive
component monitoring.
(5) A listing of each monitor sequence, execution frequency and
typical duration.
(6) A listing of typical malfunction thresholds for each monitor.
(7) For OBD parameters that deviate from the typical parameters,
the OBD description shall indicate the deviation for the vehicles it
applies to and provide a separate listing of the typical values for
those vehicles.
(8) Identification and scaling information necessary to interpret
and understand data available to a generic scan tool through Diagnostic
Message 8 pursuant to SAE Recommended Practice J1939-73, which is
incorporated by reference in section X.
(9) For vehicles below 14,000 pounds, EPA requires that any
information related to the service, repair, installation or replacement
of parts or systems developed by third party (Tier 1) suppliers for
OEMs, to the extent they are made available to franchise dealerships.
EPA believes that Tier 1 suppliers are an important element of the
market related to vehicles below 14,000 pounds and EPA is requesting
comment on the role that Tier 1 suppliers play in the heavy-duty market
above 14,000 pounds and the need to extend this provision to the heavy-
duty industry above 14,000 pounds.
(10) Any information on other systems that can directly effect the
emission system within a multiplexed system (including how information
is sent between emission-related system modules and other modules on a
multiplexed bus),
(11) Any information regarding any system, component, or part of a
vehicle monitored by the OBD system that could in a failure mode cause
the OBD system to illuminate the malfunction indicator light (MIL).
(12) Any other information relevant to the diagnosis and completion
of an emissions-related repair. This information includes, but is not
limited to, information needed to start the vehicle when the vehicle is
equipped with an anti-theft or similar system that disables the engine
described below in paragraph (13). This information also includes any
OEM-specific emissions-related diagnostic trouble codes (DTCs) and any
related service bulletins, trouble shooting guides, and/or repair
procedures associated with these OEM-specific DTCs.
(13) For vehicles below 14,000 pounds, EPA requires that OEMs make
available computer or anti-theft system initialization information
necessary for the proper installation of on-board computers on motor
vehicles that employ integral vehicle security systems or the repair or
replacement of any other emission-related part. We did not finalize a
provision that would require OEMs to make this information available on
the OEM's Web site unless they chose to do so. However, we did finalize
a provision requiring that the OEM's Web site contain information on
alternate means for obtaining the information and/or ability to perform
reintialization. EPA is proposing to expand this provision to OEMs for
vehicles above 14,000 pounds and requests comment on the prevalence of
this type of repair, the means and methods for performing this type of
repair and the need to extend this provision to the heavy-duty industry.
In addition, EPA's current service information rules require that,
beginning with the 2008 model year, all OEM systems will be designed in
such a way that no special tools or processes will be necessary to
perform re-initialization. In other words, EPA expects that the re-
initialization of vehicles can be completed with generic aftermarket
tools, a pass-through device, or an inexpensive OEM-specific cable. EPA
finalized this provision for vehicles below 14,000 pounds to prevent
the need for aftermarket service providers to invest in expensive OEM-
specific or specialty tools to complete an emissions-related repair
that does not occur very frequently, but does in fact occur. In the
June 2003 final rule, EPA gave OEMs a significant amount of lead time
to either separate the need for reinitialization from an emissions
related repair or otherwise redesign the reinitialization process in
such a way that it does not require the use of special tools. EPA
requests comment on the need for such a provision for the above 14,000
pound market. To the extent that such a provision may be needed for the
heavy-duty arena, EPA also requests comment and what lead-time might be
needed to meet EPA's goal of not relying on special tools or processes
to perform reinitialization.
Information for making emission-related repairs does not include
information used to design and manufacture parts, but may include OEM
changes to internal calibrations, and other indirect information, as
discussed below.
2. What Are the Proposed Requirements for Web-Based Delivery of the
Required Information?
a. OEM Web Sites
Today's action proposes a provision that would require OEMs to make
available in full-text all of the information outlined above, on
individual OEM Web sites. Today's action further proposes that each OEM
launch their individual Web sites with the required information within
6 months of publication of the final rule for all 2010 and later model
year vehicles. The only proposed exceptions to the full-text
requirements are training information, anti-theft information, and
indirect information.
b. Timeliness and Maintenance of Information on OEM Web Sites
Today's action proposes a provision that would require OEMs to make
available the required information on their Web site within six months
of model introduction. After this six month period, we propose that the
required information for each model must be available and updated on
the OEM Web site at the same time it is available by any means to their
dealers.
For vehicles under 14,000 pounds, EPA finalized a provision that
OEMs maintain the required information in full text on their Web sites
for at least 15 years after model introduction. After this fifteen-year
period, OEMs can archive the required service information, but it must
be made available upon request, in a format of the OEM's choice (e.g.
CD-ROM). Given the significantly longer lifetime of heavy-duty vehicles
and engines above 14,000 pounds, EPA requests comment on the need to
require that the required information be required to remain on the Web
sites for a longer period of time.
c. Accessibility, Reporting and Performance Requirements for OEM Web Sites
Performance reports that adequately demonstrate that their
individual Web sites meets the requirements outlined in Section C(1)
above will be submitted to the Administrator annually or upon

[[Page 3268]]

request by the Administrator. These reports shall also indicate the
performance and effectiveness of the Web sites by using commonly used
Internet statistics (e.g. successful requests, frequency of use, number
of subscriptions purchased, etc). EPA will issue additional direction
in the form of official manufacturer guidance to further specify the
process for submitting reports to the Administrator.
In addition, EPA is proposing a provision that requires OEMs to
launch Web sites that meet the following performance criteria:
(1) OEM Web sites shall possess sufficient server capacity to allow
ready access by all users and have sufficient downloading capacity to
assure that all users may obtain needed information without undue delay;
(2) Broken Web links shall be corrected or deleted weekly.
(3) Web site navigation does not require a user to return to the
OEM home page or a search engine in order to access a different portion
of the site.
(4) It is also proposed that any manufacturer-specific acronym or
abbreviation shall be defined in a glossary webpage which, at a
minimum, is hyperlinked by each webpage that uses such acronyms and
abbreviations. OEMs may request Administrator approval to use alternate
methods to define such acronyms and abbreviations. The Administrator
shall approve such methods if the motor vehicle manufacturer adequately
demonstrates that the method provides equivalent or better ease-of-use
to the Web site user.
(5) Indicates the minimum hardware and software specifications
required for satisfactory access to the Web site(s).
d. Structure and Cost of OEM Web Sites
In addition to the proposed requirements described above, EPA is
proposing that OEMs establish a three-tiered approach for the access to
their Web-based service information. These three tiers are proposed to
include, but are not limited to short-term, mid-term, and long-term
access to the required information.
(1) Short-Term Access
OEMs shall provide short-term access for a period of 24-72 hours
whereby an aftermarket service provider will be able to access that
OEM's Web site, search for the information they need, and purchase and/
or print it for a set fee.
(2) Mid-Term Access
OEMs shall provide mid-term access for a period of 30 days whereby
an aftermarket service provider will be able to access that OEM's Web
site, search for the information they need, and purchase and/or print
it for a set fee.
(3) Long-Term Access
OEMs shall provide long-term access for a period of 365 days
whereby an aftermarket service provider will be able to access that
OEM's Web site, search for the information they need, and purchase and/
or print it for a set fee.
In addition, for each of the tiers, we propose that OEMs make their
entire site accessible for the respective period of time and price. In
other words, we propose that an OEM may not limit any or all of the
tiers to just one make or one model.
EPA finalized the three-tiered information access approach in our
June 2003 rulemaking to accommodate the wide variety of ways in which
EPA believes aftermarket service providers utilize service information.
On the under 14,000 side, aftermarket technicians approach the service
of vehicles anywhere from servicing any make or model that comes into
their shops to specializing in one particular manufacturer. In
addition, EPA believes that there are other parties such as ``do-it-
yourself'' mechanics or Inspection/Maintenance programs that may be
interested in accessing such OEM web-sites. In addition, aftermarket
service providers for vehicles below 14,000 pounds also relay on third
party information consolidation entities such as Mitchell or All Data
to supplement OEM-specific information. These factors, in addition to
the fact that there are approximately 25ish (check this number) light-
duty vehicle manufacturers, led EPA to the conclusion that a tiered
approach to Web site access was necessary to ensure maximum
availability to the aftermarket. EPA requests comment on the nature of
aftermarket service for the heavy-duty above 14,000 pound industry and
the need for a tiered approach to information availability.
Today's action also proposes that, prior to the official launch of
OEM Web sites, each OEM will be required to present to the
Administrator a specific outline of what will be charged for access to
each of the tiers. We are further proposing that OEMs must justify
these charges, and submit to the Administrator information on the
following parameters, which include but are not limited to, the following:
(1) The price the manufacturer currently charges their branded
dealers for service information. At a minimum, this must include the
direct price charged that is identified exclusively as being for
service information, not including any payment that is incorporated in
other fees paid by a dealer, such as franchise fees. In addition, we
propose that the OEM must describe the information that is provided to
dealers, including the nature of the information (e.g., the complete
service manual), etc.; whether dealers have the option of purchasing
less than all of the available information, or if purchase of all
information is mandatory; the number of branded dealers who currently
pay for this service information; and whether this information is made
available to any persons at a reduced or no cost, and if so,
identification of these persons and the reason they receive the
information at a reduced cost.
(2) The price the manufacturer currently charges persons other than
branded dealers for service information. The OEM must describe the
information that is provided, including the nature of the information
(e.g., the complete service manual, emissions control service manual),
etc.; and the number of persons other than branded dealers to whom the
information is supplied.
(3) The estimated number of persons to whom the manufacturer would
be expected to provide the service information following implementation
of today's requirements. If the manufacturer is proposing a fee
structure with different access periods (e.g., daily, monthly and
annual periods), the manufacturer must estimate the number of users who
would be expected to subscribe for the different access periods.
A complete list of the proposed criteria for establishing
reasonable cost can be found in the proposed regulatory language for
this final rule. We are also proposing that, subsequent to the launch
of the OEM Web sites, OEMs would be required to notify the
Administrator upon the increase in price of any one or all of the tiers
of twenty percent or more accounting for inflation or that sets the
charge for end-user access over the established price guidelines
discussed above, including a justification based on the criteria for
reasonable cost as established by this regulation.
Throughout the history of the current service information
regulations, the price of service information and how price impacts the
availability of service information has been a source of significant
debate and discussion. In looking at the legislative history that led
to the inclusion of the service information mandate in the Clean Air
Act Amendments of 1990, it is clear that Congress did not intend for
the pricing of information to be an artificial barrier

[[Page 3269]]

to access. Further, Congress did not intend for information access
charges to become a profit center for OEMs. However, EPA has
interpreted that Congress did intend for OEMs to be able to recover
reasonable costs for making information available. Since the initial
implementation of the service information requirements beginning with
original 1995 final rulemaking, EPA has continued to refine the
provisions regulating the cost of service to try to balance the
Congressional intent while understanding that OEMs should be able to
recover reasonable costs for making the required information available
to the aftermarket. In fact, the relatively prescriptive nature of some
of the requirements stem directly from instances on the light-duty side
where, in the past, we believe some manufacturers deliberately priced
access to information in such a way that effectively made it
unavailable to the aftermarket. The provisions being proposed today
regarding the pricing of service information reflect many years of
implementation experience, debate, and discussion on the light-duty
side and EPA specifically requests comment from heavy-duty aftermarket
service providers on current state of pricing of OEM heavy-duty service
information and what else EPA should consider for heavy-duty that might
be different from light-duty.
e. Hyperlinking to and From OEM Web Sites
Today's action proposes a provision that requires OEMs to allow
direct simple hyperlinking to their Web sites from government Web sites
and from all automotive-related Web sites, such as aftermarket service
providers, educational institutions, and automotive associations.
f. Administrator Access to OEM Web Sites
Today's action proposes a provision that requires that the
Administrator shall have access to each OEM Web site at no charge to
the Agency. The Administrator shall have access to the site, reports,
records and other information as provided by sections 114 and 208 of
the Clean Air Act and other provisions of law.
g. Other Media
We are proposing a provision which would require OEMs to make
available for ordering the required information in some format approved
by the Administrator directly from their Web site after the proposed
full-text window of 15 years has expired. It is proposed that each OEM
shall index their available information with a title that adequately
describes the contents of the document to which it refers. In the
alternate, OEMs may allow for the ordering of information directly from
their Web site, or from a Web site hyperlinked to the OEM Web site. We
also propose that OEMs be required to list a phone number and address
where aftermarket service providers can call or write to obtain the
desired information. We also propose that OEMs must also provide the
price of each item listed, as well as the price of items ordered on a
subscription basis. To the extent that any additional information is
added or changed for these model years, OEMs shall update the index as
appropriate. OEMs will be responsible for ensuring that their
information distributors do so within one regular business day of
received the order. Items are less than 20 pages (e.g. technical
service bulletins) shall be faxed to the requestor and distributors are
required to deliver the information overnight if requested and paid for
by the ordering party.
h. Small Volume Provisions for OEM Web Sites
In the July 2003 final rulemaking, EPA finalized a provision to
provide flexibility for small volume OEMs. In particular, EPA finalized
a provision that requires OEMs who are issued certificates of
conformity with total annual sales of less than one thousand vehicles
are be exempt from the full-text Internet requirements, provided they
present to the Administrator and obtain approval for an alternative
method by which emissions-related information can be obtained by the
aftermarket or other interested parties. EPA also finalized a provision
giving OEMs with total annual sales of less than five thousand vehicles
an additional 12 months to launch their full-text Web sites.
These small-volume flexibilities are limited to the distribution
and availability of service information via the World Wide Web under
paragraph (4) of the regulations. All OEMs, regardless of volume, must
comply with all other provisions as finalized in this rulemaking. EPA
is requesting comment on the existence of small volume OEMs in the
heavy-duty arena and the need for any provisions relating to small
volume OEMs.
3. What Provisions Are Being Proposed for Service Information for Third
Party Information Providers?
The nature of the light-duty aftermarket service industry is such
that they rely to a great extent on consolidated service information
that is development by third party information providers such as
Mitchell and All-data. Third-party information providers will license
OEM service information and consolidate that information for sale to
the aftermarket. In the June 2003 final rule, EPA finalized a provision
that will require OEMs who currently have, or in the future engage in,
licensing or business arrangements with third party information
providers, as defined in the regulations, to provide information to
those parties in an electronic format in English that utilizes non-
proprietary software. Further, EPA required that any OEM licensing or
business arrangements with third party information providers are
subject to fair and reasonable cost requirements. Lastly, we expect
that OEMs will develop pricing structures for access to this
information that make it affordable to any third party information
providers with which they do business. EPA proposes to extend these
provisions to the heavy-duty vehicle and engine manufacturers beginning
with the 2010 model year.
However, EPA is specifically requesting comment on what role third-
party consolidated information plays in the heavy-duty aftermarket.
Further, EPA requests comment on the need for these, or additional
provisions, related to third-party information providers.
4. What Requirements are Being Proposed for the Availability of
Training Information?
a. Purchase of Training Materials for OEM Web Sites
In the light-duty service information final rule, EPA finalized two
provisions for access to OEM emissions-related training. First, OEMs
are required to make available for purchase on their Web sites the
following items: Training manuals, training videos, and interactive,
multimedia CD's or similar training tools available to franchised
dealerships. Second, we finalized a provision that OEMs who transmit
emissions-related training via satellite or the Internet must tape
these transmissions and make them available for purchase on their Web
sites within 30 days after the first transmission to franchised
dealerships. Further, all of the items included in this provision must
be shipped within 24 hours of the order being placed and are to be made
available at a reasonable price. We also finalized a provision that
will allow for an exception to the 24 hour shipping requirement in
those circumstances where orders exceed supply and additional time is
needed by the distributor to reproduce the item being ordered. For
subsequent model years,

[[Page 3270]]

the required information must be made available for purchase within
three months of model introduction, and then be made available at the
same time it is made available to franchised dealerships.
EPA is proposing to extend these provisions to the heavy-duty
industry and requests comment on the need to so or to develop other
provisions pertaining to the availability of training information for
the heavy-duty aftermarket.
b. Third Party Access to OEM Training Material
In the light-duty final rule, we also finalized a provision that
requires OEMs who utilize Internet and satellite transmissions to
present emissions-related training to their dealerships to make these
same transmissions available to third party training providers. In this
way, we believe we are providing at least one opportunity for
aftermarket technicians to receive similar emissions-related training
information as provided to dealerships, thus furthering the goals and
letter of section 202(m)(5). This requirement only requires OEMs to
provide the same information to legitimate aftermarket training
providers as is provided to dealerships and aftermarket service
providers. It is not a requirement to license OEM copyrighted materials
to these entities.
OEMs may take reasonable steps to protect their copyright to the
extent some or all of this material may be copyrighted and may refuse
to do business with any party that does not agree to such steps.
However, we do expect OEMs to use fair business practices in its
dealings with these third parties, in keeping with the ``fair and
reasonable price'' requirements in these regulations. OEMs may not
charge unreasonable up-front fees for access to these transmissions,
but OEMs may require a royalty, percentage or other arranged fee based
limits of on a per-use or enrollment subscription basis.
EPA requests comment on the need to expand the light-duty
requirements to the heavy-duty sector. EPA also requests comments on
any additional provisions it should consider to ensure that heavy-duty
aftermarket service providers and trainers have sufficient access to
OEM training information at a fair and reasonable price. EPA also
requests comments on the types of training that is currently
development by heavy-duty OEMs and what processes may already be in
place for availability to the aftermarket.
5. What Requirements Are Being Proposed for Reprogramming of Vehicles?
The 2003 final rule required that light-duty OEMs comply with SAE
J2534, ``Recommended Practice for Pass-Thru Vehicle Programming''. EPA
understands that the heavy-duty industry has a similar standard in
place that is similar to SAE J2534 specification for reprogramming.
Therefore, today's action proposes two options for pass-thru
reprogramming. We are proposing that heavy-duty OEMs comply with SAE
J2534 beginning with 2010 model year. In the alternate, heavy-duty OEMs
may comply with the Technology and Maintenance Council's Recommended
Practice RP1210a, ``Windows Communication API,'' July 1999 beginning in
the 2010 model year. We will also propose a provision that will require
that reprogramming information be made available within 3 months of
vehicle introduction for new models.
6. What Requirements are Being Proposed for the Availability of
Enhanced Information for Scan Tools for Equipment and Tool Companies?
a. Description of Information That Must Be Provided
Today's action proposes a provision that requires OEMs to make
available to equipment and tool companies all generic and enhanced
information, including bi-directional control and data stream
information. In addition, it is proposed that OEMs must make available
the following information.
(i) The physical hardware requirements for data communication (e.g.
system voltage requirements, cable terminals/pins, connections such as
RS232 or USB, wires, etc.).
(ii) ECU data communication (e.g. serial data protocols,
transmission speed or baud rate, bit timing requirements, etc.).
(iii) Information on the application physical interface (API) or
layers. (i.e., processing algorithms or software design descriptions
for procedures such as connection, initialization, and termination).
(iv) Vehicle application information or any other related service
information such as special pins and voltages or additional vehicle
connectors that require enablement and specifications for the enablement.
(v) Information that describes which interfaces, or combinations of
interfaces, from each of the categories as described in paragraphs
(g)(12)(vii)(A) through (D) of the regulatory language.
b. Distribution of Enhanced Diagnostic Information
Today's action proposes a provision that will require the above
information for generic and enhanced diagnostic information be provided
to aftermarket tool and equipment companies with whom appropriate
licensing, contractual, and confidentiality agreements have been
arranged. This information shall be made available in electronic format
using common document formats such as Microsoft Excel, Adobe Acrobat,
Microsoft Word, etc. Further, any OEM licensing or business
arrangements with equipment and tool companies are subject to a fair
and reasonable cost determination.
7. What Requirements Are Being Proposed for the Availability of
OEM-Specific Diagnostic Scan Tools and Other Special Tools?
a. Availability of OEM-Specific Diagnostic Scan Tools
Today's action proposes a provision that OEMs must make available
for sale to interested parties the same OEM-specific scan tools that
are available to franchised dealerships, except as discussed below. It
is proposed that these tools shall be made available at a fair and
reasonable price. It is also proposed, that these tools shall also be
made available in a timely fashion either through the OEM Web site or
through an OEM-designated intermediary.
b. Decontenting of OEM-Specific Diagnostic Scan Tools
Today's action proposes a provision that requires OEMs who opt to
remove non-emissions related content from their OEM-specific scan tools
and sell them to the persons specified in paragraph (g)(2)(i) and
(f)(2)(i) of the regulatory language for this final rule shall adjust
the cost of the tool accordingly lower to reflect the decreased value
of the scan tool. It is proposed that all emissions-related content
that remains in the OEM-specific tool shall be identical to the
information that is contained in the complete version of the OEM-
specific tool. Any OEM who wishes to implement this option must request
approval from the Administrator prior to the introduction of the tool
into commerce.
c. Availability of Special Tools
The 2003 final rule precluded light-duty OEMs from using special
tools to extinguish the malfunction indicator light (MIL) beginning
with model year 2004. For model years 1994 through 2003, the final rule
required OEMs who

[[Page 3271]]

currently require such tools to extinguish the MIL must release the
necessary information to equipment and tool companies to design a
comparable generic tool. We also required that this information shall
be made available no later than one month following the effective date
of the Final Rule. EPA requests comment on this or other special tools
that may be unique to the heavy-duty industry and on the need for
provisions covering these tools.
8. Which Reference Materials are Being Proposed for Incorporation by
Reference?
Today's action will finalize a provision requiring that OEMs comply
with the following SAE Recommended Practices.
(1) SAE Recommended Practice J2403 (October 1998), ``Medium/Heavy-
Duty EE Systems Diagnosis Nomenclature'' beginning with the 2010 model
year.
(2) SAE Recommended Practice J2534 (February, 2002), ``Recommended
Practice for Pass-Thru Vehicle Reprogramming''. EPA will require that
OEMs comply with SAE J2534 beginning with the 2010 model year.
(3) SAE Recommended Practice J1939-73.
(4) ISO/DIS 15031-5 April 30, 2002.

V. What Are the Emissions Reductions Associated With the Proposed OBD
Requirements?

In the 2007HD highway rule, we estimated the emissions reductions
we expected to occur as a result of the emissions standards being made
final in the rule. Since the OBD requirements contained in today's
proposal are considered by EPA to be an important element of the 2007HD
highway program and its ultimate success, rather than a new element
being included as an addition to that program, we are not estimating
emissions reductions associated with today's proposal. Instead, we
consider the new 2007/2010 tailpipe emissions standards and fuel
standards to be the drivers of emissions reductions and HDOBD to be
part of the assurance we all have that those emissions reductions are
indeed realized. Therefore, this analysis presents the emissions
reductions estimated for the 2007HD highway program. Inherent in those
estimates is an understanding that, while emissions control systems
sometimes malfunction, they presumably are repaired in a timely manner.
Today's proposed OBD requirements would provide substantial tools to
assure that our presumption will be realized by helping to ensure that
emission control systems continue to operate properly throughout their
life. We believe that the OBD requirements proposed today would lead to
more repairs of malfunctioning or deteriorating emission control
systems, and may also lead to emission control systems that are more
robust throughout the life of the engine and less likely to trigger
illumination of MILs. The requirements would therefore provide greater
assurance that the emission reductions expected from the Clean Diesel
Trucks and Buses program will actually occur. Viewed from another
perspective, while the OBD requirements would not increase the emission
reductions that we estimated for the 2007HD highway rule, they would be
expected to lead to actual emission reductions in-use compared with a
program with no OBD system.
The costs associated with HDOBD were not fully estimated in the
2007HD highway rule. Those costs are more fully considered in section
VI of this preamble. These newly developed HDOBD costs are added to
those costs estimated for the 2007/2010 standards and a new set of
costs for those standards are presented in section VII. Section VII
also calculates a new set of costs per ton associated with the 2007/
2010 standards which include the previously estimated costs and
emissions reductions for the 2007/2010 standards and the newly
estimated costs associated with today's HDOBD proposal.
Here we present the emission benefits we anticipate from heavy-duty
vehicles as a result of our 2007/2010 NO_X, PM, and NMHC
emission standards for heavy-duty engines. The graphs and tables that
follow illustrate the Agency's projection of future emissions from
heavy-duty vehicles for each pollutant. The baseline case represents
future emissions from heavy-duty vehicles at present standards
(including the MY2004 standards). The controlled case represents the
future emissions from heavy-duty vehicles once the new 2007/2010
standards are implemented. A detailed analysis of the emissions
reductions associated with the 2007/2010 HD highway standards is
contained in the Regulatory Impact Analysis for that final rule.\70\
The results of that analysis are presented in Table V.A-1 and in
Figures V.A-1 through V.A-3.
---------------------------------------------------------------------------

\70\ Regulatory Impact Analysis: Heavy-Duty Engine and Vehicle
Standards and Highway Diesel Fuel Sulfur Control Requirements;
EPA420-R-00-026; December 2000.

Table V.A-1.--Annual Emissions Reductions Associated With the 2007HD
Highway Program
[thousand short tons]
------------------------------------------------------------------------
Year NOX PM NMHC
------------------------------------------------------------------------
2007......................................... 58 11 2
2010......................................... 419 36 21
2015......................................... 1,260 61 54
2020......................................... 1,820 82 83
2030......................................... 2,570 109 115
------------------------------------------------------------------------

[[Page 3272]]
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BILLING CODE 6560-50-C
There were additional estimated emissions reductions associated
with the 2007HD highway rule--namely CO, SO_X, and air
toxics. We have not presented those additional emissions reductions
here since, while HDOBD will identify malfunctions and hasten their
repair with the result of reducing all emissions constituents, these
additional emissions are not those specifically targeted by OBD systems.

VI. What Are the Costs Associated With the Proposed OBD Requirements?

Estimated engine costs are broken into variable costs and fixed
costs. Variable costs are those costs associated with any new hardware
required to meet the proposed requirements, the associated assembly
time to install that hardware, and the increased warranty costs
associated with the new hardware. Variable costs are additionally
marked up to account for both manufacturer and dealer overhead and
carrying costs. The manufacturer's carrying cost was estimated to be
four percent of the direct costs to account for the capital cost of the
extra inventory and the incremental costs of insurance, handling, and
storage. The dealer's carrying cost was estimated to be three percent
of their direct costs to account for the cost of capital tied up in
inventory. We adopted this same approach to markups in the 2007HD highway
rule and our more recent Nonroad Tier 4 rule based on industry input.
Fixed costs considered here are those for research and development
(R&D), certification, and production evaluation testing. The fixed
costs for engine R&D are estimated to be incurred over the four-year
period preceding introduction of the engine. The fixed costs for
certification include costs associated with demonstration testing of
OBD parent engines including the ``limit'' parts used to demonstrate
detection of malfunctions at or near the applicable OBD thresholds, and
generation of certification documentation. Production evaluation
testing includes testing real world products for standardization
features, monitor function, and performance ratios. The certification
costs are estimated to be incurred one year preceding introduction of
the engine while the production evaluation testing is estimated to
occur in the same year as introduction.
The details of our cost analysis are contained in the technical
support document which can be found in the docket for this rule.\71\ We
have only summarized the results of that analysis here and point the
reader to the technical support document for details. We request
comment on all aspects of our cost analysis.
---------------------------------------------------------------------------

\71\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID# EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

A. Variable Costs for Engines Used in Vehicles Over 14,000 Pounds

The variable costs we have estimated represent those costs
associated with various sensors that we believe would have to be added
to the engine to provide the required OBD monitoring capability. For
the 2010 model year, we believe that upgraded computers and the new
sensors needed for OBD would result in costs to the buyer of $40 and
$50 for diesel and gasoline engines, respectively. For the 2013 model
year, we have included costs associated with the dedicated MIL and its
wiring resulting in a hardware cost to the buyer of $50 and $60 for
both diesel and gasoline engines, respectively. By multiplying these
costs per engine by the projected annual sales we get annual costs of
around $40-50 million for diesel engines and $3-4 million for gasoline
engines, depending on sales. The 30 year net present value of the
annual variable costs would be $666 million and $352 million at a three
percent and a seven percent discount rate, respectively. These costs
are summarized in Table VI.A-1.

[[Page 3274]]

Table VI.A-1.--OBD Variable Costs for Engines Used in Vehicles Over
14,000 Pounds
[All costs in $millions except per engine costs; 2004 dollars]
------------------------------------------------------------------------
Diesel Gasoline Total
------------------------------------------------------------------------
Cost per engine (2010-2012)...... $40 $50 n/a
Cost per engine (2013+).......... 50 60 n/a
Annual Variable Costs in 2010 \a\ 14 1 $15
Annual Variable Costs in 2013 \a\ 38 3 40
Annual Variable Costs in 2030 \a\ 48 4 52
30 year NPV at a 3% discount rate 620 47 666
30 year NPV at a 7% discount rate 328 25 352
------------------------------------------------------------------------
\a\ Annual variable costs increase as projected sales increase.

B. Fixed Costs for Engines Used in Vehicles Over 14,000 Pounds

We have estimated fixed costs for research and development (R&D),
certification, and production evaluation testing. The R&D costs include
the costs to develop the computer algorithms required to diagnose
engine and emission control systems, and the costs for applying the
developed algorithms to each engine family and to each variant within
each engine family. R&D costs also include the testing time and effort
needed to develop and apply the OBD algorithms. The certification costs
include the costs associated with testing of durability engines (i.e.,
the OBD parent engines), the costs associated with generating the
``limit'' parts that are required to demonstrate OBD detection at or
near the applicable emissions thresholds, and the costs associated with
generating the necessary certification documentation. Production
evaluation testing costs included the costs associated with the three
types of production testing: standardization features, monitor
function, and performance ratios.
Table VI.B-1 summarizes the R&D, certification, and production
evaluation testing costs that we have estimated. The R&D costs we have
estimated were totaled and then spread over the four year period prior
to implementation of the requirements for which the R&D is conducted.
By 2013, all of the R&D work would be completed in advance of 100
percent compliance in 2013; hence, R&D costs are zero by 2013.
Certification costs are higher in 2013 than in 2010 because 2010
requires one engine family to comply while 2013 requires all engine
families to comply. The 30 year net present value of the annual fixed
costs would be $291 million and $241 million at a three percent and a
seven percent discount rate, respectively.

Table VI.B-1.--OBD Fixed Costs for Engines Used in Vehicles Over 14,000 Pounds
[All costs in $millions; 2004 dollars]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Diesel Gasoline
--------------------------------------------------------------------------------------------------
Certification Certification
R&D & PE testing Subtotal R&D & PE testing Subtotal Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual OBD Fixed Costs in given years:
2010............................................. $51 $0.2 $52 $0.9 < $0.1 $1 $53
2013............................................. 0 0.4 0.4 0 < 0.1 < 0.1 0.4
2030............................................. 0 3 3 0 < 0.1 < 0.1 3
30 year NPV at the given discount rate:
3 percent........................................ $263 $17 $280 $10 $0.3 $10 $291
7 percent........................................ 223 10 232 9 0.2 9 241
--------------------------------------------------------------------------------------------------------------------------------------------------------

C. Total Costs for Engines Used in Vehicles Over 14,000 Pounds

The total OBD costs for engines used in vehicles over 14,000 pounds
are summarized in Table VI.C-1. As shown in the table, the 30 year net
present value cost is estimated at $1 billion and $594 million at a
three percent and a seven percent discount rate, respectively. These
costs are much lower than the 30 year net present value costs estimated
for the 2007HD highway emissions standards which were $25 billion and
$15 billion at a three percent and a seven percent discount rate,
respectively, for diesel and gasoline engines. Including the cost for
the diesel fuel changes resulted in 30 year net present value costs for
that rule of $70 billion and $42 billion at a three percent and a seven
percent discount rate, respectively. See section VII for more details
regarding the cost estimates from the 2007HD highway final rule.

[[Page 3275]]

Table VI.C-1.--OBD Total Costs for Engines Used in Vehicles Over 14,000
Pounds
[All costs in $millions; 2004 dollars]
------------------------------------------------------------------------
Diesel Gasoline Total
------------------------------------------------------------------------
Annual OBD Total Costs in given years
------------------------------------------------------------------------
2010................................... $65 $2 $67
2013................................... 38 3 41
2030................................... 51 4 55
------------------------------------------------------------------------
30 year NPV at the given discount rate
------------------------------------------------------------------------
3%..................................... 900 57 957
7%..................................... 560 34 594
------------------------------------------------------------------------

D. Costs for Diesel Heavy-Duty Vehicles and Engines Used in Heavy-duty
Vehicles Under 14,000 Pounds

The total OBD costs for 8,500 to 14,000 pound diesel applications
are summarized in Table VI.D-1. As shown in the table, the 30 year net
present value cost is estimated at $6 million and $5 million at a three
percent and a seven percent discount rate, respectively. These costs
represent the incremental costs of the proposed additional OBD
requirements, as compared to our current OBD requirements, for 8,500 to
14,000 pound diesel applications and do not represent the total costs
for 8,500 to 14,000 pound diesel OBD. We are proposing no changes to
the 8,500 to 14,000 pound gasoline requirements so, therefore, have
estimated no costs for gasoline vehicles. Details behind these
estimated costs can be found in the technical support document
contained in the docket for this rule.\72\
---------------------------------------------------------------------------

\72\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID# EPA-HQ-OAR-2005-0047-0008.

Table VI.D-1.--Total OBD Costs for 8,500 to 14,000 Pound Diesel
Applications
[All costs in $millions; 2004 dollars]
------------------------------------------------------------------------
Diesel Gasoline Total
------------------------------------------------------------------------
Annual OBD Total Costs in given years
------------------------------------------------------------------------
2010................................... $0.1 $0 $0.1
2013................................... 0 0 0
2030................................... 0.4 0 0.4
------------------------------------------------------------------------
30 year NPV at the given discount rate
------------------------------------------------------------------------
3%..................................... 6 0 6
7%..................................... 5 0 5
------------------------------------------------------------------------

VII. What are the Updated Annual Costs and Costs per Ton Associated
With the 2007/2010 Heavy-duty Highway Program?

In the 2007HD highway rule, we estimated the costs we expected to
occur as a result of the emissions standards being made final in that
rule. As noted in section V, we consider the OBD requirements contained
in today's proposal to be an important element of the 2007HD highway
program and its ultimate success and not a new element being included
as an addition to that program. In fact, without the proposed OBD
requirements we would not expect the emissions reductions associated
with the 2007/2010 standards to be fully realized because emissions
control systems cannot be expected to operate without some need for
repair which, absent OBD, may well never be done. However, as noted in
section VI, because we did not include an OBD program in the 2007HD
highway program, we did not estimate OBD related costs at that time. We
have now done so and those costs are presented in section VI.
Here we present the OBD costs as part of the greater 2007HD highway
program. To do this, we present both the costs developed for that
program and the additional OBD costs presented in section VI. We also
calculate a new set of costs per ton associated with the 2007/2010
standards which include the previously estimated costs and emissions
reductions for the 2007/2010 standards and the newly estimated costs
associated with today's HDOBD proposal.
Note that the costs estimates associated with the 2007HD highway
program were done using 1999 dollars. We have estimated OBD costs in
2004 dollars. We consulted the Producer Price Index (PPI) for ``Motor
vehicle parts manufacturing-new exhaust system parts'' developed by the
Bureau of Labor Statistics and found that the PPI for such parts had
actually decreased from 1999 to 2004.\73\ This suggests that the cost
to produce exhaust system parts has decreased since 1999. For clarity,
rather than adjusting downward the 2007HD highway program costs from
1999 dollars, or adjusting upward the OBD costs from 2004 dollars, we
have chosen to present the 2007HD highway rule costs as they were
presented in that final rule alongside the OBD costs presented in section
VI. In short, we are ignoring the PPI effect in the following tables.
---------------------------------------------------------------------------

\73\ See http://www.bls.gov/ppi; All other motor vehicle parts mfg;
Exhaust system parts, new; series ID PCU3363993363993; Base date 8812.
---------------------------------------------------------------------------

A. Updated 2007 Heavy-Duty Highway Rule Costs Including OBD

Table VII.A-1 shows the 2007HD highway program costs along with the
estimated OBD related costs.

Table VII.A-1.--Updated 2007HD Highway Program Costs, Including New OBD-Related Costs, Net Present Value of
Annual Costs for the Years 2006-2035
[All costs in $millions]
----------------------------------------------------------------------------------------------------------------
2007 HD Highway Final Rule
---------------------------------------------------- Updated
Gasoline Proposed HD total
Discount rate Diesel engine & Diesel fuel Original OBD program
engine vehicle costs total costs costs
costs costs
----------------------------------------------------------------------------------------------------------------
3 percent......................... $23,721 $1,514 $45,191 $70,427 $963 $71,389
7 percent......................... 14,369 877 26,957 42,203 599 42,802
----------------------------------------------------------------------------------------------------------------

[[Page 3276]]

B. Updated 2007 Heavy-Duty Highway Rule Costs per Ton Including OBD

Table VII.B-1 shows the 2007HD highway program costs per ton of
pollutant reduced. These numbers are straight from the 2007HD highway
final rule which contains the details regarding the split between
NO_X+NMHC and PM related costs.

Table VII.B-1.--Original 2007HD Highway Program Costs, Emissions Reductions, and $/Ton Reduced
[Net present values are for annual costs for the years 2006-2035]
----------------------------------------------------------------------------------------------------------------
30 year NPV 30 year NPV
Discount rate Pollutant cost reduction $/ton
($billions) (million tons)
----------------------------------------------------------------------------------------------------------------
3 percent............................. NOX+NMHC................ 54.6 30.6 1,780
PM...................... 16.0 1.4 11,790
7 percent............................. NOX+NMHC................ 34.9 16.2 2,150
PM...................... 10.3 0.8 13,610
----------------------------------------------------------------------------------------------------------------

Table VII.B-2 shows the updated 2007HD highway program costs per
ton of pollutant reduced once the new OBD costs have been included. For
the split between NO_X+NMHC and PM-related OBD costs, we have
used a 50/50 allocation. As shown in Table VII.B-2, the OBD costs
associated with the proposed OBD requirements have little impact on the
overall costs and costs per ton of emissions reduced within the context
of the 2007HD highway program.

Table VII.B-2.--Updated 2007HD Highway Program Costs, Emissions Reductions, and $/ton Reduced Including OBD
Related Costs
[Net present values are for annual costs for the years 2006-2035]
----------------------------------------------------------------------------------------------------------------
30 year NPV 30 year NPV
Discount rate Pollutant cost reduction $/ton
($billions) (million tons)
----------------------------------------------------------------------------------------------------------------
3 percent............................. NOX+NMHC................ 55.1 30.6 1,800
PM...................... 16.5 1.4 12,210
7 percent............................. NOX+NMHC................ 35.2 16.2 2,170
PM...................... 10.6 0.8 14,130
----------------------------------------------------------------------------------------------------------------

VIII. What Are the Requirements for Engine Manufacturers?

A. Documentation Requirements

The OBD system certification requirements would require
manufacturers to submit OBD system documentation that represents each
engine family. The certification documentation would be required to
contain all of the information needed to determine if the OBD system
meets the proposed OBD requirements. The proposed regulation lists the
information that would be required as part of the certification
package. If any of the information in the certification package is the
same for all of a manufacturer's engine families (e.g., the OBD system
general description), the manufacturer would only be required to submit
one set of documents each model year for such items that would cover
all of its engine families.
While the majority of the proposed OBD requirements would apply to
the engine and be incorporated by design into the engine control module
by the engine manufacturer, a portion of the proposed OBD requirements
would apply to the vehicle and not be self-contained within the engine.
Examples include the proposed requirements to have a MIL in the
instrument cluster and a diagnostic connector in the cab compartment.
As is currently done by the engine manufacturers, a build specification
is provided to vehicle manufacturers detailing mechanical and
electrical specifications that must be adhered to for proper
installation and use of the engine (and to maintain compliance with
emissions standards). We expect engine manufacturers would continue to
follow this practice so that the vehicle manufacturer would be able to
maintain compliance with the proposed OBD regulations. Installation
specifications would be expected to include instructions regarding the
location, color, and display icon of the MIL (as well as electrical
connections to ensure proper illumination), location and type of
diagnostic connector, and electronic VIN access. During the
certification process, in addition to submitting the details of all of
the diagnostic strategies and other information required, engine
manufacturers would be required to submit a copy of the OBD-relevant
installation specifications provided to vehicle manufacturers and a
description of the method used by the engine manufacturer to ensure
vehicle manufacturers adhere to the provided installation
specifications (e.g., required audit procedures or signed agreements to
adhere to the requirements). We are requiring that this information be
submitted to us to provide a reasonable level of verification that the
proposed OBD requirements would indeed be satisfied. In summary, engine
manufacturers would be responsible for submitting a certification
package that includes:
? A detailed description of all OBD monitors, including
monitors on signals or messages coming from other modules upon which
the engine control unit relies to perform other OBD monitors; and,
? A copy of the OBD-relevant installation specifications
provided to vehicle manufacturers/chassis builders and the method used
to reasonably ensure compliance with those specifications.
As was discussed in the context of our implementation schedule (see
section II.G.1), the proposed regulations would allow engine
manufacturers to establish

[[Page 3277]]

OBD groups consisting of more than one engine family with each having
similar OBD systems. The manufacturer could then submit only one set of
representative OBD information from each OBD group. We anticipate that
the representative information would normally consist of an application
from a single representative engine rating within each OBD group. In
selecting the engine ratings to represent each OBD group, consideration
should be given to the exhaust emission control components for all
engine families and ratings within an OBD group. For example, if one
engine family within an OBD group has additional emission control
devices relative to another family in the group (e.g., the first family
has a DPF+SCR while the second has only a DPF), the representative
rating should probably come from the first engine family. Manufacturers
seeking to consolidate several engine families into one OBD group would
be required to get approval of the grouping prior to submitting the
information for certification.
Two of the most important parts of the certification package would
be the OBD system description and summary table. The OBD system
description would include a complete written description for each
monitoring strategy outlining every step in the decision-making process
of the monitor, including a general explanation of the monitoring
conditions and malfunction criteria. This description should include
graphs, diagrams, and/or other data that would help our compliance
staff understand how each monitor works and interacts. The OBD summary
table would include specific parameter values. This table would provide
a summary of the OBD system specifications, including: the component/
system, the DTC identifying each related malfunction, the monitoring
strategy, the parameter used to detect a malfunction and the
malfunction criteria limits against which the parameter is evaluated,
any secondary parameter values and the operating conditions needed to
run the monitor, the time required to execute and complete a monitoring
event for both a pass decision and a fail decision, and the criteria or
procedure for illuminating the MIL. In these tables, manufacturers
would be required to use a common set of engineering units to simplify
and expedite the review process.
We are also proposing that the manufacturer submit a logic
flowchart for each monitor that would illustrate the step-by-step
decision process for determining malfunctions. Additionally, we would
need any data that supports the criteria used to determine malfunctions
that cause emissions to exceed the specified malfunction thresholds
(see Tables II.B-1 and II.C-1). The manufacturer would have to include
data that demonstrates the probability of misfire detection by the
misfire monitor over the full engine speed and load operating range
(for gasoline engines only) or the capability of the misfire monitor to
correctly identify a ``one cylinder out'' misfire for each cylinder
(for diesel engines only), a description of all the parameters and
conditions necessary to begin closed-loop fuel control operation (for
gasoline engines only), closed-loop EGR control (for diesel engines
only), closed-loop fuel pressure control (for diesel engines only), and
closed-loop boost control (for diesel engines only). We would also need
a listing of all electronic powertrain input and output signals
(including those not monitored by the OBD system) that identifies which
signals are monitored by the OBD system, and the emission data from the
OBD demonstration testing (as described below). Lastly, the
manufacturer would be expected to provide any other OBD-related
information necessary to determine the OBD compliance status of the
manufacturer's product line.

B. Catalyst Aging Procedures

For purposes of determining the catalyst malfunction criteria for
diesel NMHC converting catalysts, SCR catalysts, and lean
NO_X catalysts, and for gasoline catalysts, where those
catalysts are monitored individually, the manufacturer must use a
catalyst deteriorated to the malfunction criteria using methods
established by the manufacturer to represent real world catalyst
deterioration under normal and malfunctioning engine operating
conditions. For purposes of determining the catalyst malfunction
criteria for diesel NMHC converting catalysts, SCR catalysts, and lean
NO_X catalysts, and for gasoline catalysts, where those
catalysts are monitored in combination with other catalysts, the
manufacturer would have to submit their catalyst system aging and
monitoring plan to the Administrator as part of their certification
documentation package. The plan would include the description, emission
control purpose, and location of each component, the monitoring
strategy for each component and/or combination of components, and the
method for determining the applicable malfunction criteria including
the deterioration/aging process.

C. Demonstration Testing

While the proposed certification documentation requirements
discussed above would require manufacturers to submit technical details
of each monitor (e.g., how each monitor worked, when the monitor would
run), we would still need some assurance that the manufacturer's OBD
monitors are indeed calibrated correctly and are able to detect a
malfunction before an emissions threshold is exceeded. Thus, we are
proposing that manufacturers conduct certification demonstration
testing of the major monitors to verify the malfunction threshold
values. This testing would be required on one to three demonstration
engines per year. Before receiving a certificate of compliance, the
manufacturer would be required to submit documentation and emissions
data demonstrating that the major OBD monitors are able to detect a
malfunction when emissions exceed the emissions thresholds. On each
demonstration engine, this testing would consist of the following two
elements:
? Testing the OBD system with ``threshold'' components
(i.e., components that are deteriorated or malfunctioning right at the
threshold required for MIL illumination); and,
? Testing the OBD system with ``worst case'' components.
This element of the demonstration test would have to be done for the
DPF and any NO_X aftertreatment system only.
By testing with both threshold components (i.e., the best
performing malfunctioning components) and with worst case components
(i.e., the worst performing malfunctioning components), we would be
better able to verify that the OBD system should perform as expected
regardless of the level of deterioration of the component. This could
become increasingly important with new technology aftertreatment
devices that could be subject to complete failure (such as DPFs) or
even to tampering by vehicle operators looking to improve fuel economy
or vehicle performance. We believe that, given the likely combinations
of emissions control hardware, a diesel engine manufacturer would
likely need to conduct 8 to 10 emissions tests per demonstration engine
to satisfy these requirements and a gasoline engine manufacturer would
likely need to conduct five to seven emissions tests per demonstration
engine.\74\
---------------------------------------------------------------------------

\74\ For diesel engines these would include: the fuel system;
misfire (HCCI engines); EGR, turbo boost control, DPF,
NO_X adsorber or SCR system, NMHC catalyst, exhaust gas
sensors, VVT, and possible other emissions controls (see section
II.D.5). For gasoline engines these would include: the fuel system,
misfire, EGR, cold start strategy, secondary air system, catalyst,
exhaust gas sensors, VVT, and possible other emissions controls (see
section II.D.5). Some of these may require more than one emissions
test while others may not require any due to the use of a functional
monitor rather than an emissions threshold monitor.

---------------------------------------------------------------------------

[[Page 3278]]

1. Selection of Test Engines
To minimize the test burden on manufacturers, we are proposing that
this testing be done on only one to three demonstration engines per
year per manufacturer rather than requiring that all engines be tested.
Such an approach should still allow us to be reasonably sure that
manufacturers have calibrated their OBD systems correctly on all of
their engines. This also spreads the test burden over several years and
allows manufacturers to better utilize their test cell resources. This
approach is consistent with our approach to demonstration testing to
existing emissions standards where a parent engine is chosen to
represent each engine family and emissions test data for only that
parent engine are submitted to EPA.\75\
---------------------------------------------------------------------------

\75\ For over 14,000 pound OBD, we are proposing a different
definition of a ``parent'' engine than is used for emissions
certification. This is discussed at length in section II.G.
---------------------------------------------------------------------------

The number of demonstration engines manufacturers would be required
to test would be aligned with the phase-in of OBD in the 2010 and 2013
model years and based on the year and the total number of engine
families the manufacturer would be certifying for that model year.
Specifically, for the 2010 model year when a manufacturer is only
required to implement OBD on a single engine family, demonstration
testing would be required on only one engine (a single engine rating
within the one engine family). This would be the OBD parent rating as
discussed in section II.G. For the 2013 model year, manufacturers would
be required to conduct demonstration testing on one to three engines
per year (i.e., one to three OBD parent ratings). The number of parent
ratings would be chosen depending on the total number of engine
families certified by the manufacturer. A manufacturer certifying one
to five engine families in the given year would be required to test one
demonstration engine. A manufacturer certifying six to ten engine
families in the given year would be required to test two demonstration
engines, and a manufacturer certifying more than ten engine families in
the given year would be required to test three demonstration engines.
For the 2016 and subsequent model years, we would work closely with
CARB staff and the manufacturer to determine the parent ratings so that
the same ratings are not acting as the parents every year. In other
words, our definitions for the OBD parent ratings as discussed here
apply only during the years 2010 through 2012 and again for the years
2013 through 2015.
Given the difficulty and expense in removing an in-use engine from
a vehicle for engine dynamometer testing, this demonstration testing
would likely represent nearly all of the OBD emission testing that
would ever be done on these engines. Requiring a manufacturer who is
fully equipped to do such testing, and already has the engines on
engine dynamometers for emission testing, to test one to three engines
per year would be a minimal testing burden that provides invaluable
and, in a practical sense, otherwise unobtainable proof of compliance
with the OBD emissions thresholds.
Regarding the selection of which engine ratings would have to be
demonstrated, manufacturers would be required to submit descriptions of
all engine families and ratings planned for the upcoming model year. We
would review the information and make the selection(s) in consultation
with CARB staff and the manufacturer. For each engine family and
rating, the information submitted by the manufacturer would need to
identify engine model(s), power ratings, applicable emissions standards
or family emissions limits, emissions controls on the engine, and
projected engine sales volume. Factors that would be used in selecting
the one to three engine ratings for demonstration testing include, but
are not limited to, new versus old/carryover engines, emissions control
system design, possible transition point to more stringent emissions
standards and/or OBD emissions thresholds, and projected sales volume.
2. Required Testing
Regarding the actual testing, the manufacturer would be required to
perform ``single fault'' testing using the applicable test procedure
and with the appropriate components/systems set at the manufacturer
defined malfunction criteria limits for the following monitors:
? For diesel engines: Fuel system; misfire; EGR; turbo boost
control; NMHC catalyst; NO_X catalyst/adsorber; DPF; exhaust
gas sensors; VVT; and any other monitor that would fall within the
discussion of section II.D.5.
? For gasoline engines: Fuel system; misfire; EGR; cold
start strategy; secondary air; catalyst; exhaust gas sensors; VVT; and
any other monitor that would fall within the discussion of section II.D.5.
Such ``single fault'' testing would require that, when performing a
test for a specific parameter, that parameter must be operating at the
malfunction criteria limit while all other parameters would be
operating within normal characteristics (unless the malfunction
prohibits some other parameter from operating within its normal
characteristics). Also, the manufacturer would be allowed to use
computer modifications to cause the specific parameter to operate at
the malfunction limit provided the manufacturer can demonstrate that
the computer modifications produce test results equivalent to an
induced hardware malfunction. Lastly, for each of these testing
requirements, wherever the manufacturer has established that only a
functional check is required because no failure or deterioration of the
specific tested component/system could result in an engine's emissions
exceeding the applicable emissions thresholds, the manufacturer would
not be required to perform a demonstration test. In such cases, the
manufacturer could simply provide the data and/or engineering analysis
used to determine that only a functional test of the component/system
was required.
Manufacturers required to submit data from more than one engine
rating would be granted some flexibility by allowing the data to be
collected under less rigorous testing requirements than the official
FTP or SET certification test. That is, for the possible second and
third engine ratings required for demonstration testing, manufacturers
would be allowed to submit data using internal sign-off test procedures
that are representative of the official FTP or SET in lieu of running
the official test. Commonly used procedures include the use of engine
emissions test cells with less rigorous quality control procedures than
those required for the FTP or SET or the use of forced cool-downs to
minimize time between tests. Manufacturers would still be liable for
meeting the OBD emissions thresholds on FTPs and/or SETs conducted in
full accordance with the Code of Federal Regulations. Nonetheless, this
latitude would allow them to use some short-cut methods that they have
developed to assure themselves that the system is calibrated to the
correct level without incurring the additional testing cost and burden
of running the official FTP or SET on every demonstration engine.
For the demonstration engine(s), a manufacturer would be required
to use an engine(s) aged for a minimum of 125

[[Page 3279]]

hours plus exhaust aftertreatment devices aged to be representative of
full useful life. Manufacturers would be expected to use, subject to
approval, an aging process that ensures that deterioration of the
exhaust aftertreatment devices is stabilized sufficiently such that it
properly represents the performance of the devices at the end of their
useful life.
3. Testing Protocol
We are proposing that the manufacturer be allowed to use any
applicable test cycle for preconditioning test engines prior to
conducting each of the emissions tests discussed above. Additional
preconditioning can be done if the manufacturer has provided data and/
or engineering analyses that demonstrate that additional
preconditioning is necessary.
The manufacturer would then set the system or component of interest
at the criteria limit(s) prior to conducting the applicable
preconditioning cycle(s). If more than one preconditioning cycle is
being used, the manufacturer may adjust the system or component of
interest prior to conducting the subsequent preconditioning cycle.
However, the manufacturer may not replace, modify, or adjust the system
or component of interest following the last preconditioning cycle.
After preconditioning, the test engine would be operated over the
applicable test cycle to allow for the initial detection of the tested
system or component malfunction. This test cycle may be omitted from
the testing protocol if it is unnecessary. If required by the
designated monitoring strategy, a cold soak may be performed prior to
conducting this test cycle. The test engine would then be operated over
the applicable exhaust emission test.
A manufacturer required to test more than one test engine may use
internal calibration sign-off test procedures (e.g., forced cool downs,
less frequently calibrated emission analyzers) instead of official test
procedures to obtain this emissions test data for all but one of the
required test engines. However, the manufacturer should use sound
engineering judgment to ensure that the data generated using such
alternative test/sign-off procedures are good data because
manufacturers would still be responsible for meeting the malfunction
criteria when emissions tests are performed in accordance with official
test procedures.
Manufacturers would be allowed to use alternative testing
protocols, even chassis testing, for demonstration of MIL illumination
if the engine dynamometer emissions test cycle does not allow all of a
monitor's enable conditions to be satisfied. Manufacturers wanting to
do so would be required to demonstrate the technical necessity for
using their alternative test cycle and that using it demonstrates that
the MIL would illuminate during in-use operation with the
malfunctioning component.
4. Evaluation Protocol
For all demonstration tests on parent engines, we would expect that
the MIL would activate upon detecting the malfunctioning system or
component, and that it should occur before the end of the first engine
start portion of the emissions test. If the MIL were to activate prior
to emissions exceeding the applicable malfunction criteria, no further
demonstration would be required. With respect to the misfire monitor
demonstration test, if the manufacturer has elected to use the minimum
misfire malfunction criterion of one percent (as is allowed), then no
further demonstration would be required provided the MIL were to
illuminate during a test with an implanted misfire of one percent.
If the MIL does not activate when the system or component being
tested is set at its malfunction criteria limits, then the criteria
limits or the OBD system would not be considered acceptable. Retesting
would be required with more tightly controlled criteria limits (i.e.,
recalibrated limits) and/or another suitable system or component that
would result in MIL activation. If the criteria limits are
recalibrated, the manufacturer would be required to confirm that the
systems and components that were tested prior to recalibration would
still function properly and as required.
5. Confirmatory Testing
We may choose to confirmatory test a demonstration engine to verify
the emissions test data submitted by the manufacturer. Any such
confirmatory testing would be limited to the engine rating represented
by the demonstration engine(s) (i.e., the parent engine(s)). To do so,
we, or our designee, would install appropriately deteriorated or
malfunctioning components (or simulate a deteriorated or malfunctioning
component) in an otherwise properly functioning engine of the same
engine family and rating as the demonstration engine. Such confirmatory
testing would be done on those OBD monitors for which demonstration
testing had been conducted as described in this section. The
manufacturer would be required to make available, upon Administrator
request, a test engine and all test equipment--e.g., malfunction
simulators, deteriorated components--necessary to duplicate the
manufacturer's testing.

D. Deficiencies

Our under 14,000 pound OBD requirements have contained a deficiency
provision for years. The OBD deficiency provision was first introduced
on March 23, 1995 (60 FR 15242), and was revised on December 22, 1998
(63 FR 70681). Consistent with that provision, we are proposing a
deficiency provision for over 14,000 pound OBD. We believe that, like
has occurred and even still occurs with under 14,000 pound OBD, some
manufacturers will encounter unforeseen and generally last minute
problems with some of their OBD monitoring strategies despite having
made a good faith effort to comply with the requirements. Therefore, we
are proposing a provision that would permit certification of an over
14,000 pound OBD system with ``deficiencies'' in cases where a good
faith effort to fully comply has been demonstrated. In making
deficiency determinations, we would consider the extent to which the
proposed OBD requirements have been satisfied overall based on our
review of the certification application, the relative performance of
the given OBD system compared to systems that truly are fully compliant
with the proposed OBD requirements, and a demonstrated good-faith effort
on the part of the manufacturer to both meet the proposed requirements in
full and come into full compliance as expeditiously as possible.
We believe that having the proposed deficiency provision is
important because it would facilitate OBD implementation by allowing
for certification of an engine despite having a relatively minor
shortfall. Note that we do not expect to certify engines with OBD
systems that have more than one deficiency, or to allow carryover of
any deficiency to the following model year unless it can be
demonstrated that correction of the deficiency requires hardware and/or
software modifications that cannot be accomplished in the time
available, as determined by the Administrator.\76\ Nonetheless, we
recognize that there may be situations where more than one deficiency
is necessary and appropriate, or where carry-over of a deficiency or
deficiencies for more than one year is necessary and

[[Page 3280]]

appropriate. In such situations, more than one deficiency, or carry-
over for more than one year, may be approved, provided the manufacturer
has demonstrated an acceptable level of effort toward full OBD
compliance. Most importantly, the deficiency provisions cannot be used
as a means to avoid compliance or delay implementation of any OBD
monitors or as a means to compromise the overall effectiveness of the
OBD program.
---------------------------------------------------------------------------

\76\ The CARB HDOBD rulemaking has a provision to charge fees
associated with OBD deficiencies 13 CCR 1971.1(k)(3), Docket
ID# EPA-HQ-OAR-2005-0047-0006. We have never had and are not
proposing any such fee provision.
---------------------------------------------------------------------------

There has often been some confusion by manufacturers regarding what
CARB has termed ``retroactive'' deficiencies. The CARB rule states
that, ``During the first 6 months after commencement of normal
production, manufacturers may request that the Executive Officer grant
a deficiency and amend an engine's certification to conform to the
granting of the deficiencies for each aspect of the monitoring system:
(a) Identified by the manufacturer (during testing required by section
(l)(2) or any other testing) to be functioning different than the
certified system or otherwise not meeting the requirements of any
aspect of section 1971.1; and (b) reported to the Executive Officer.''
\77\ We have never had and are not proposing any such retroactive
deficiency provision. We have regulations in place that govern
situations, whether they be detected by EPA or by the manufacturer,
where in-use vehicles or engines are determined to be functioning
differently than the certified system.\78\ We refer to these
regulations as our defect reporting requirements and manufacturers are
required to comply with these regulations, even for situations deemed
by CARB to be ``retroactive'' deficiencies, unless the defect is
corrected prior to the sale of engines to an ultimate purchaser. In
other words, a retroactive deficiency granted by the Executive Officer
does not preclude a manufacturer from complying with our defect
reporting requirements.
---------------------------------------------------------------------------

\77\ See 13 CFR 1971.1(k)(6)), Docket ID# EPA-HQ-OAR-2005-0047-0006.
\78\ See 40 CFR 85.1903.
---------------------------------------------------------------------------

E. Production Evaluation Testing

The OBD system is a complex software and hardware system, so there
are many opportunities for unintended interactions that can result in
certain elements of the system not working as intended. We have seen
many such mistakes in the under 14,000 pound arena ranging from OBD
systems that are unable to communicate any information to a scan tool
to monitors that are unable to store a DTC and illuminate the MIL.
While over 14,000 pound heavy-duty vehicles are very different from
light-duty vehicles in terms of emission controls and OBD monitoring
strategies, among other things, these types of problems do not depend
on these differences and, as such, are as likely to occur with over
14,000 pound OBD as they are with under 14,000 pound OBD. Additionally,
we believe that there is great value in having manufacturers self-test
actual production end products that operate on the road, as opposed to
pre-production products, where errors can be found in individual
subsystems that may work fine by themselves but not when integrated
into a complete product (e.g., due to mistakes like improper wiring).
Therefore, we are proposing that manufacturers self-test a small
fraction of their product line to verify compliance with the OBD
requirements. The test requirements are divided into three distinct
sections with each section representing a test for a different portion
of the OBD requirements. These three sections being: compliance with
the applicable SAE and/or ISO standardization requirements; compliance
with the monitoring requirements for proper DTC storage and MIL
illumination; and, compliance with the in-use monitoring performance ratios.
1. Verification of Standardization Requirements
An essential part of the OBD system is the requirement for
standardization. The proposed standardization requirements include
items as simple as the location and shape of the diagnostic connector
(where technicians can ``plug in'' a scan tool to the onboard computer)
to more complex subjects concerning the manner and format in which DTC
information is accessed by technicians via a ``generic'' scan tool.
Manufacturers must meet these standardization requirements to
facilitate the success of the proposed OBD program because they ensure
consistent access by all repair technicians to the stored information
in the onboard computer. The need for consistency is even greater when
considering the potential use of OBD system checks in inspection and
maintenance (I/M) programs for heavy-duty. Such OBD base I/M checks
would benefit from having access to the diagnostic information in the
onboard computer via a single ``generic'' scan tool instead of
individual tools for every make and model of truck that might be
inspected. For OBD based inspections to work effectively and
efficiently, all engines/vehicles must be designed and built to meet
all of the applicable standardization requirements.
While we anticipate that the vast majority of vehicles would comply
with all of the standardization requirements, some problems involving
the communication between vehicles and ``generic'' scan tools are
likely to occur in the field. The cause of such problems could range
from differing interpretations of the existing standardization
requirements to possible oversights by design engineers or hardware
inconsistencies or even last-minute production changes on the assembly line.
To minimize the chance for such problems on future over 14,000
pound trucks, we are proposing that engine manufacturers be required to
test a sample of production vehicles from the assembly line to verify
that the vehicles have indeed been designed and built to the required
specifications for communication with a ``generic'' scan tool. We are
proposing that manufacturers be required to test complete vehicles to
ensure that they comply with some of the basic ``generic'' scan tool
standardization requirements, including those that are essential for
proper inspection in an I/M setting. Ideally, manufacturers would be
required to test one vehicle for each truck and engine model
combination that is introduced into commerce. However, for a large
engine manufacturer, this can be in the neighborhood of 5,000 to 10,000
unique combinations making it unreasonable to require testing of every
combination. Therefore, we are proposing that manufacturers test 10
such combinations per engine family. Given that a typical engine family
has roughly five different engine ratings, this works out to testing
only around two vehicles per engine rating.
More specifically, manufacturers would be required to test one
vehicle per software ``version'' released by the manufacturer. With
proper demonstration, manufacturers would be allowed to group different
calibrations together to be demonstrated by a common vehicle. Prior to
acquiring these data, the proposal would require engine manufacturers
to submit for approval a test plan verifying that the vehicles
scheduled for testing would be representative of all vehicle
configurations (e.g., each engine control module variant coupled with
and without the other available vehicle components that could affect
scan tool communication such as automatic transmission or hybrid
powertrain control modules). The plan would have to include details on
all the different applications and configurations that would be tested.

[[Page 3281]]

As noted, manufacturers would be required to conduct this testing
on actual production vehicles, not stand-alone engines. This is
important since controllers that work properly in a stand alone setting
(e.g., the engine before it is installed in a vehicle) may have
interaction problems when installed and attempting to communicate with
other vehicle controllers (e.g., the transmission controller). In such
a case, separate testing of the controllers would be blind to the
problem. Since heavy-duty engine manufacturers are expected to sell the
same engine (with the same calibration) to various vehicle
manufacturers who would put them in different final products (e.g.,
with different transmission control modules), the same communication
problem would be expected in each final product.
This testing should occur soon enough in the production cycle to
provide manufacturers with early feedback regarding the existence of
any problems and time to resolve the problem prior to the entire model
year's products being introduced into the field. We are proposing that
the testing be done and the data submitted to us within either three
months of the start of normal engine production or one month of the
start of vehicle production, whichever is later.
To be sure that all manufacturers are testing vehicles to the same
level of stringency, we are proposing that engine manufacturers submit
documentation outlining the testing equipment and methods they intend
to use to perform this testing. We anticipate that engine manufacturers
and scan tool manufacturers would probably develop a common piece of
hardware and software that could be used by all engine manufacturers at
the end of the vehicle assembly line to meet this requirement. Two
different projects (SAE J1699 and LOC3T) have developed such equipment
in response to California OBD II requirements.\79\ The equipment is
currently being used to test 2005 and 2006 model year vehicles under
14,000 pounds. We believe that similar equipment could be developed for
vehicles over 14,000 pounds in time for the 2013 model year. Ideally,
the equipment and the test procedure would verify each and every
requirement of the communication specifications including the various
physical layers, message structure, response times, and message
content. Presumably, any such verification equipment would not replace
the function of existing ``generic'' scan tools used by repair
technicians or I/M inspectors. The equipment would likely be custom-
designed and be used for the express purpose of this assembly line
testing (i.e., it would not include all of the necessary diagnostic
features needed by repair technicians).
---------------------------------------------------------------------------

\79\ 13 CCR 1968.2, August 11, 2006, Docket ID# EPA-HQ-OAR-2005-0047-0005.
---------------------------------------------------------------------------

2. Verification of Monitoring Requirements
As noted above, the OBD system is a complex software and hardware
system, so there are many opportunities for unintended interactions
that can result in certain elements of the system not working as
intended. The causes of possible problems vary from simple typing
errors in the software code to component supplier hardware changes late
in development or just prior to start of production. Given the
complexity of OBD monitors and their associated algorithms, there can
be thousands of lines of software code required to meet the diagnostic
requirements. Implementing that code without interfering with the
software code required for normal operation is and will be a very
difficult task with many opportunities for human error. We expect that
manufacturers will conduct some validation testing on end products to
ensure that there are no problems that would be noticed by the vehicle
operator. We believe that manufacturers should include in such
verification testing an evaluation of the OBD system (e.g., does the
MIL illuminate as intended in response to a malfunction?).
Therefore, we are proposing that engine manufacturers be required
to perform a thorough level of validation testing on at least one
production vehicle and up to two more production engines per model
year. The production vehicles/engines required for testing would have
to be equipped with/be from the same engine families and ratings as
used for the certification demonstration testing described in section
VIII.B.3. If a manufacturer demonstrated one, two, or three engines for
certification, then at least one production vehicle and perhaps an
additional one to two engines would have to be tested, respectively. We
would work with the manufacturer and CARB staff to determine the actual
vehicles and engines to test.
The testing itself would consist of implanting or simulating
malfunctions to verify that virtually every single engine-related OBD
monitor on the vehicle correctly identifies the malfunction, stores an
appropriate DTC, and illuminates the MIL. Manufacturers would not be
required to conduct any emissions testing. Instead, for those
malfunctions designed against an emissions threshold, the manufacturer
would simply implant or simulate a malfunction and verify detection,
DTC storage, and MIL illumination. Actual ``threshold'' parts would not
be needed for such testing. Implanted malfunctions could use severely
deteriorated parts if desired by the manufacturer since the point of
the testing is to verify detection, DTC storage, and MIL illumination.
Upon submitting the data to the Administrator, the manufacturer would
be required to also provide a description of the testing and the
methods used to implant or simulate each malfunction. Note that testing
of specific monitors would not be required if the manufacturer can show
that no possible test exists that could be done on that monitor without
causing physical damage to the production vehicle. We are proposing
that the testing be completed and reported to us within six months
after the manufacturer begins normal engine production. This should
provide early feedback on the performance of every monitor on the
vehicle prior to too many entering production. Upon good cause, we may
extend the time period for testing.
Note that, in their HDOBD rule,\80\ CARB allows, as an incentive to
perform a thorough validation test, a manufacturer to request that any
problem discovered during this self-test be treated as a
``retroactive'' deficiency. As discussed in section VIII.B.4, we do not
have a provision for retroactive deficiencies. Importantly, a
retroactive deficiency granted by the Executive Officer does not
preclude a manufacturer from complying with our defect reporting
requirements. This issue was discussed in more detail in section VIII.B.4.
---------------------------------------------------------------------------

\80\ 13 CCR 1971.1, Docket ID# EPA-HQ-OAR-2005-0047-0006.
---------------------------------------------------------------------------

3. Verification of In-Use Monitoring Performance Ratios
We are proposing that manufacturers track the performance of
several of the most important monitors on the engine to determine how
often they are monitoring during in-use operation. These requirements
are discussed in more detail in section II.E. To summarize that
discussion, monitors would be expected to execute in the real world and
meet a minimum acceptable performance level determined as the ratio of
the number of good monitoring events to the number of actual trips. The
ratio being proposed is 10 percent, meaning that monitors should
execute during at least 10 percent of the trips taken by the engine/
vehicle. Monitors

[[Page 3282]]

that perform below the minimum ratio would be subject to remedial
action and possibly recall. However, the minimum ratio is not effective
until the 2013 and later model years. For the 2010 through 2012 model
year engines certified to today's proposed OBD requirements, we are
proposing that the data be collected even though the minimum ratio is
not yet effective. The data gathered on these engines will help to
determine whether the 10 percent ratio is appropriate for all
applications and, if not, we would intend to propose a change to the
proposed requirement to reflect that learning.
We are proposing that manufacturers gather these data on production
vehicles rather than engines. Since not every vehicle can be evaluated,
we are proposing that manufacturers generate groups of engine/vehicle
combinations to ensure adequate representation of the fleet.
Specifically, manufacturers would be required to separate production
vehicles into monitoring performance groups based on the following
criteria and submit performance ratio data representative of each group:
? Emission control system architecture type--All engines
that use the same or similar emissions control system architecture and
associated monitoring system would be in the same emission architecture
category. By architecture we mean engines with EGR+DPF+SCR, or
EGR+DPF+NO_X Adsorber, or EGR+DPF-only, etc.
? Application type--Within an emission architecture
category, engines would be separated by vehicle application. The
separate application categories would be based on three
classifications: engines intended primarily for line-haul chassis
applications, engines intended primarily for urban delivery chassis
applications, and all other engines.
We are proposing that these data be submitted to us within 12
months of the production vehicles entering the market. Upon submitting
the collected data to us, the manufacturer would also be required to
provide a detailed description of how the data were gathered, how
vehicles were grouped to represent sales of their engines, and the
number of engines tested per monitoring performance group.
Manufacturers would be required to submit performance ratio data from a
sample of at least 15 vehicles per monitoring performance group. For
example, a manufacturer with two emission control system architectures
sold into each of the line-haul, urban delivery, and ``other''
groupings, would be required to submit data on up to 90 vehicles (i.e.,
2 x 3 x 15). We are proposing that these data be collected every year.
Some manufacturers may find it easiest to collect data from vehicles
that come in to its authorized repair facilities for routine
maintenance or warranty work during the time period required, while
others may find it more advantageous to hire a contractor to collect
the data. Upon good cause, we may extend the time period for testing.
As stated before, the data collected under this program are
intended primarily to provide an early indication that the systems are
working as intended in the field, to provide information to ``fine-
tune'' the proposed requirement to track the performance of monitors,
and to provide data to be used to develop a more appropriate minimum
ratio for future regulatory revisions. The data are not intended to
substitute for testing that we would perform for enforcement reasons to
determine if a manufacturer is complying with the minimum acceptable
performance ratios. In fact, the data collected would not likely meet
all the required elements for testing to make an official determination
that the system is noncompliant. As such, we believe the testing would
be of most value to manufacturers since monitor performance problems
can be corrected prior to EPA conducting a full enforcement action that
could result in a recall.

IX. What are the Issues Concerning Inspection and Maintenance Programs?

A. Current Heavy-Duty I/M Programs

While there are currently no regulatory requirements for heavy-duty
inspection and maintenance (I/M), and no State Implementation Plan
(SIP) credit given for heavy-duty I/M, a recent review shows that
programs in the United States as well as abroad are currently testing
heavy-duty diesel and heavy-duty gasoline vehicles as part of their
Inspection and Maintenance programs. A recent study found that the
mandated vehicle emission I/M programs in the CAAA of 1990, originally
required in areas where ambient levels of ozone and CO exceeded the
national standards, are being utilized as a framework as diesel PM
becomes increasingly recognized as an important health concern in the
United States.\81\ Some countries outside the U.S., particularly
developing countries, have been seeking to improve air quality by
implementing both light-duty and heavy-duty I/M programs.
---------------------------------------------------------------------------

\81\ Review of Light-Duty Diesel and Heavy-Duty Diesel/Gasoline
Inspection Programs, St. Denis and Lindner, Journal of the Air and
Waste Management Association, December 2005.
---------------------------------------------------------------------------

In the U.S., the light-duty fleet has become cleaner. As a result,
heavy-duty vehicles are responsible for an increasing contribution of
the mobile source emission inventory. EPA has responded to the
increased contribution by promulgating technology-promoting standards,
to be phased in during the years leading up to 2010. Some non-
attainment areas are implementing HD vehicle I/M programs to improve
their regional air quality. The current tailpipe emissions measurements
result in a number of issues, so other technologies such as remote
sensing are being examined. Interrogation of the OBD system on over
14,000 pound vehicles would likely be a candidate I/M test method.
As of 2004, according to the aforementioned study, many I/M
programs in the U.S. have developed a wide range of emission tests for
HD diesel vehicles and HD gasoline vehicles. 19 States currently test
HD diesel vehicles (these are: AZ, CA, CO, CT, ID, IL, KY, ME, MD, MA,
NV, NH, NJ, NM, NY, OH, UT, VT, WA); 25 states test HD gasoline
vehicles (these are: AK, AZ, CA, CO, CT, ID, IL, IN, KY, MD, MA, NV,
NJ, NM, NY, NC, OH, OR, PA, TN, TX, UT, VA, WA, WI). Canada, China,
Singapore, Sweden, and the United Kingdom test HD diesel vehicles.
Lastly, Germany, Singapore, and Sweden test HD gasoline vehicles.
Whether or not voluntary or regulated inspection and maintenance
programs become prominent, heavy-duty OBD should be designed to allow
ease of interrogation to maximize the potential of this technology to
help realize environmental benefit. There is evidence that localities
are utilizing this strategy in their air quality protection programs.
There is also a wealth of light-duty OBD experience to support making
an I/M-type test as user-friendly as possible so technician training
and scan tool designs do not limit the ability to assess a vehicle's status.

B. Challenges for Heavy-Duty I/M

There are a number of challenges that are being discovered as
programs implement heavy-duty I/M. Existing HD I/M programs utilize of
a number of different emission test types, such as snap-idle testing
(based on SAE J1667), loaded cruise testing (chassis dynamometer), ASM
testing, Transient IMXXX, Two-Speed Idle or Curb Idle, and Lug-down
testing. Projections of heavy-duty vehicle inventory contributions for
VOC, NO_X, PM, and toxics have substantiated the need for
more stringent regulations. Repairs

[[Page 3283]]

based on individual emission test types, such as opacity testing, may
target and reduce one pollutant (e.g., PM) while neglecting or
increasing others (e.g., NO_X). A sound test should
effectively control all harmful pollutants, thus must be able to
measure multiple pollutants--specifically PM and NO_X emissions.
Systems capable of measuring both pollutants at the same time have
to date been prohibitively expensive for I/M programs, and
traditionally require a heavy-duty dynamometer so that vehicles can be
tested under load. Recent work has begun to investigate the use of
remote sensing and other technologies for measuring heavy-duty gaseous
and PM emissions. While this technology has not yet been routinely
implemented in HD vehicle I/M programs to date, the impetus to identify
more robust or user-friendly emission testing strategies exists.
Portable emissions measurement systems (PEMS) are not really conducive
to an I/M environment at this time because the units are very costly,
require a great deal of expertise to operate, and require considerable
time for completing a test. Such systems are best suited for intensive
analysis of emissions performance on a limited number of vehicles
rather than the widespread testing of nearly all vehicles as is the
attempt in most I/M programs. All these factors heighten the potential
that OBD systems will be utilized in I/M programs for vehicles over
14,000 pounds.

C. Heavy-Duty OBD and I/M

Heavy-duty OBD should be designed with the anticipation that there
may be new use of OBD to help insure local or regional emission
benefits. If multiple individuals are querying OBD, standardization of
testing equipment and protocol, and information format and availability
should be considered to maximize the effective use of this technology.
Many of the lessons learned from the use of light-duty OBD in I/M
programs point to a need to ensure standard protocols for testing, so
that test equipment and data collection requirements can be
accommodated in system designs. Along with common connectors, data
formats, and specific parameter monitoring requirements, future
technologies enabling standardization of data stream logic (e.g.,
built-in checks, broadcasted updates, etc.) and other currently non-
existing strategies may be attractive to minimize training requirements
for test personnel and data management for model year-specific information.
Due to the regional or national registrations of many heavy-duty
vehicles, there is the potential that eventual I/M use of OBD to
control heavy-duty vehicle emission exceedences could be at the fleet
or corporate level, rather than at the state level as is the current
light-duty convention. Stakeholders will need to inform the debate but
today's HD I/M programs may not follow the same development pattern as
light-duty I/M programs did a decade ago. The lessons learned from
light-duty OBD I/M should be complemented with early data on HD I/M
programs being piloted in the U.S. and globally.
As one example, Ontario's Ministry of the Environment has prepared
a report on their Heavy-Duty Drive Clean program. This study developed
estimates of emissions benefits for inspected diesel vehicles and
compares them to estimated baseline emissions for the case with no
Drive Clean program, for calendar years 2000, 2001, and 2002. According
to this study, over the three years of the program the total
accumulated emission reductions generated by the program's operation
were estimated to be 1092 tonnes of PM10 emissions, 654 tonnes of HC
emissions, and 721 tonnes of NO_X emissions.\82\ This
particular study utilized opacity testing, and compared failed and
fixed vehicles for different model year vehicles and for different
weight classes. The malperformance model developed originally by Radian
Corporation for ARB in 1986 was utilized since the statistical
correlation between smoke opacity an mass emissions is weak, especially
in newer vehicles; and the EPA MOBILE model assume zero deterioration
of emissions for most HD diesel engines, thereby implying no benefit
for I/M. The relationship between maintenance and emission
deterioration is complicated by the use of high efficiency
aftertreatment devices, which lose emission conversion efficiency with
age, so this model's basic premise is likely appropriate only until the
year 2008. Nevertheless, as the benefits of inspection and maintenance
become more clearly articulated, the interest in assessing test
methodologies that provide ease of use as well as multi-pollutant
screening will likely increase. For these reasons consideration of
potential I/M program use of OBD for the heavy-duty fleet is warranted,
and should include lessons-learned from the light-duty fleet as well as
anticipate new strategies for utilizing OBD information.
---------------------------------------------------------------------------

\82\ ``Drive Clean Program Emission Benefit Analysis and
Reporting--Heavy-Duty Diesel Vehicles,'' Canada Ministry of the
Environment, October 2003.
---------------------------------------------------------------------------

We request comment with respect to the level of interest in I/M
programs that make use of the proposed OBD system on over 14,000 pound
vehicles. Specifically, are states interested in I/M for over 14,000
pound vehicles that mirrors existing programs for passenger cars and
other light trucks? For those that might be interested, does the
proposed OBD system meet the needs of their potential I/M program?

X. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

This action is not a ``significant regulatory action'' under the
terms of Executive Order (EO) 12866 (58 FR 51735, October 4, 1993) and
is, therefore, not subject to review under the EO.
EPA prepared an analysis of the potential costs associated with
this action. This analysis is contained in the technical support
document.\83\ A copy of the analysis is available in the docket and was
summarized in section VI of this preamble.
---------------------------------------------------------------------------

\83\ Draft Technical Support Document, HDOBD NPRM, EPA420-D-06-
006, Docket ID# EPA-HQ-OAR-2005-0047-0008.
---------------------------------------------------------------------------

B. Paperwork Reduction Act

The proposed information collection requirements for this action
have been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The
Information Collection Request (ICR) document prepared by EPA has been
assigned EPA ICR number 1684.09. Under Title II of the Clean Air Act
(42 U.S.C. 7521 et seq.; CAA), EPA is charged with issuing certificates
of conformity for those engines that comply with applicable emission
standards. Such a certificate must be issued before engines may be
legally introduced into commerce. EPA uses certification information to
verify that the proper engine prototypes have been selected and that
the necessary testing has been performed to assure that each engine
complies with emission standards. In addition, EPA also has the
authority under Title II of the Clean Air to ensure compliance by
require in-use testing of vehicles and engines. EPA is proposing to
require additional information at the time of certification to ensure
that that on-board diagnostic (OBD) requirements are being met. EPA is
also proposing that manufacturers conduct and report the results of in-
use testing of the OBD systems to

[[Page 3284]]

demonstrate that they are performing properly. Therefore, EPA is
proposing 207 hours of annual burden per each of the 12 respondents to
conduct the OBD certification, compliance, and in-use testing
requirements proposed by this action. EPA estimates that the total of
the of the 2484 hours of annual cost burden will be $16,018 per
respondent for a total annual industry cost burden for the 12
respondents of $1,236,481.
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. technology and systems
for the purposes of collecting, validating, and verifying. This
includes the time needed to review instructions; develop, acquire,
install, and utilize information, processing and maintaining
information, and disclosing and providing information; adjust the
existing ways to comply with any previously applicable instructions and
requirements; train personnel to be able to respond to a collection of
information; search data sources; complete and review the collection of
information; and transmit or otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR are listed in 40 CFR part 9.
To comment on the Agency's need for this information, the accuracy
of the provided burden estimates, and any suggested methods for
minimizing respondent burden, including the use of automated collection
techniques, EPA has established a public docket for this rule, which
includes this ICR, under Docket ID number EPA-HQ-OAR-2005-0047. Submit
any comments related to the ICR for this proposed rule to EPA and OMB.
See the ADDRESSES section at the beginning of this notice for where to
submit comments to EPA. Send comments to OMB at the Office of
Information and Regulatory Affairs, Office of Management and Budget,
725 17th Street, NW., Washington, DC 20503, Attention: Desk Office for
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after January 24, 2007, a comment to OMB is best
assured of having its full effect if OMB receives it by February 23,
2007. The final rule will respond to any OMB or public comments on the
information collection requirements contained in this proposal.

C. Regulatory Flexibility Act (RFA), as Amended by the Small Business
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 601 et. seq.

The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
For purposes of assessing the impacts of today's proposed rule on
small entities, small entity is defined as: (1) A motor vehicle
manufacturer with fewer than 1,000 employees; (2) a motor vehicle
converter with fewer than 750 employees; (3) a small governmental
jurisdiction that is a government of a city, county, town, school
district or special district with a population of less than 50,000; and
(4) a small organization that is any not-for-profit enterprise which is
independently owned and operated and is not dominant in its field.
After considering the economic impacts of today's proposed rule on
small entities, we have determined that this action would not have a
significant economic impact on a substantial number of small entities.
This proposed rule would not have any adverse economic impact on small
entities. Today's rule places new requirements on manufacturers of
large engines meant for highway use. These are large manufacturers.
Today's rule also changes existing requirements on manufacturers of
passenger car and smaller heavy-duty engines meant for highway use.
These changes place no meaningful new requirements on those manufacturers.

D. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for federal agencies to assess the
effects of their regulatory actions on state, local, and tribal
governments, and the private sector. Under section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to state, local, and tribal governments, in
the aggregate, or to the private sector, of $100 million or more for
any single year. Before promulgating a rule for which a written
statement is needed, section 205 of the UMRA generally requires EPA to
identify and consider a reasonable number of regulatory alternatives
and to adopt the least costly, most cost-effective, or least burdensome
alternative that achieves the objectives of the rule. The provisions of
section 205 do not apply when they are inconsistent with applicable
law. Moreover, section 205 allows EPA to adopt an alternative that is
not the least costly, most cost-effective, or least burdensome
alternative if the Administrator publishes with the final rule an
explanation of why such an alternative was not adopted.
Before EPA establishes any regulatory requirement that may
significantly or uniquely affect small governments, including tribal
governments, it must have developed under section 203 of the UMRA a
small government agency plan. The plan must provide for notifying
potentially affected small governments, enabling officials of affected
small governments to have meaningful and timely input in the
development of EPA regulatory proposals with significant Federal
intergovernmental mandates, and informing, educating, and advising
small governments on compliance with the regulatory requirements.
This rule contains no federal mandates (under the regulatory
provisions of Title II of the UMRA) for State, local, or tribal
governments or the private sector. The rule imposes no enforceable
duties on any of these entities. Nothing in the rule would
significantly or uniquely affect small governments. We have determined
that this rule does not contain a federal mandate that may result in
estimated expenditures of more than $100 million to the private sector
in any single year. Therefore, the requirements of the UMRA do not
apply to this action.

E. Executive Order 13132: Federalism

Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
This proposed rule does not have federalism implications. It will
not have substantial direct effects on the States, on the relationship
between the national

[[Page 3285]]

government and the States, or on the distribution of power and
responsibilities among the various levels of government, as specified
in Executive Order 13132. This proposed rule places new requirements on
manufacturers of large engines meant for highway use and changes
existing requirements on manufacturers of passenger car and smaller
heavy-duty engines meant for highway use. These changes do not affect
States or the relationship between the national government and the
States. Thus, Executive Order 13132 does not apply to this rule.
In the spirit of Executive Order 13132, and consistent with EPA
policy to promote communications between EPA and State and local
governments, EPA specifically solicits comment on this proposed rule
from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (59 FR 22951, November 9, 2000),
requires EPA to develop an accountable process to ensure ``meaningful
and timely input by tribal officials in the development of regulatory
policies that have tribal implications.'' This proposed rule does not
have tribal implications, as specified in Executive Order 13175.
Today's rule does not uniquely affect the communities of American
Indian tribal governments since the motor vehicle requirements for
private businesses in today's rule would have national applicability.
Furthermore, today's rule does not impose any direct compliance costs
on these communities and no circumstances specific to such communities
exist that would cause an impact on these communities beyond those
discussed in the other sections of today's document. Thus, Executive
Order 13175 does not apply to this rule.

G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks

Executive Order 13045, ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that: (1) Is determined to be ``economically significant''
as defined under Executive Order 12866; and, (2) concerns an
environmental health or safety risk that EPA has reason to believe may
have a disproportionate effect on children. If the regulatory action
meets both criteria, the Agency must evaluate the environmental health
or safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency.
This proposed rule is not subject to the Executive Order because it
is not an economically significant regulatory action as defined by
Executive Order 12866, and because the Agency does not have reason to
believe the environmental health or safety risks addressed by this
action present a disproportionate risk to children.

H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

This rule is not subject to Executive Order 13211, ``Actions
Concerning Regulations That Significantly Affect Energy Supply,
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a
significant regulatory action under Executive Order 12866.

I. National Technology Transfer Advancement Act

Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Section 12(d) of Public Law 104-113, directs EPA
to use voluntary consensus standards in its regulatory activities
unless to do so would be inconsistent with applicable law or otherwise
impractical. Voluntary consensus standards are technical standards
(e.g., materials specifications, test methods, sampling procedures, and
business practices) developed or adopted by voluntary consensus
standards bodies. The NTTAA directs EPA to provide Congress, through
OMB, explanations when the Agency decides not to use available and
applicable voluntary consensus standards.
This proposed rule references technical standards. The technical
standards being proposed are listed in Table II.F-1 of this preamble,
and directions for how they may be obtained are provided in section
II.F.1. EPA welcomes comments on this aspect of the proposed rulemaking
and, specifically, invites the public to identify other potentially-
applicable voluntary consensus standards and to explain why such
standards should be used in this regulation.

XI. Statutory Provisions and Legal Authority

Statutory authority for today's proposed rule is found in the Clean
Air Act, 42 U.S.C. 7401 et seq., in particular, sections 202 and 206 of
the Act, 42 U.S.C. 7521, 7525. This rule is being promulgated under the
administrative and procedural provisions of Clean Air Act section
307(d), 42 U.S.C. 7607(d).

List of Subjects in 40 CFR Part 86

Environmental Protection, Administrative practice and procedure,
Motor vehicle pollution.

Dated: December 11, 2006.
Stephen L. Johnson,
Administrator.

For the reasons set out in the preamble, part 86 of title 40 of the
Code of Federal Regulations is proposed to be amended as follows:

PART 86--CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES
AND ENGINES

1. The authority citation for part 86 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

2. Section 86.1 is amended as follows:
a. In the table to paragraph (b)(2) by adding new entries to the
end of the table.
b. In the table to paragraph (b)(5) by adding a new entry to the
end of the table.

Sec. 86.1 Reference materials.

* * * * *
(b) * * *
(2) * * *

------------------------------------------------------------------------
Document No. and name 40 CFR part 86 reference
------------------------------------------------------------------------

* * * * * * *
SAE J1930, Electrical/Electronic 86.010-18
Systems Diagnostic Terms,
Definitions, Abbreviations, and
Acronyms--Equivalent to ISO/TR
15031-2: April 2002.
SAE J1939, MONTH 2006, 86.010-18; 86.010-38
Recommended Practice for a
Serial Control and
Communications Vehicle Network.
SAE J1939-13, MONTH 2006, Off- 86.013-18
Board Diagnostic Connector.
SAE J1962, Diagnostic Connector-- 86.013-18
Equivalent to ISO/DIS.
15031-3: April 2002..............
SAE J1978, OBD II Scan Tool-- 86.010-18
Equivalent to ISO/DIS 15031-4:
April 2002.

[[Page 3286]]

SAE J1979, E/E Diagnostic Test 86.010-18; 86.010-38
Modes--Equivalent to ISO/DIS
15031-5: April 2002.
SAE J2012, Diagnostic Trouble 86.010-18
Code Definitions--Equivalent to
ISO/DIS 15031-6: April 2002.
SAE J2403, Medium/Heavy-Duty E/E 86.007-17; 86.010-18; 86.010-38;
Systems Diagnosis Nomenclature; 86.1806-07
August 2004.
SAE J2534, Recommended Practice 86.010-18; 86.010-38
for Pass-Thru Vehicle
Reprogramming: February 2002.
------------------------------------------------------------------------

* * * * *
(5) * * *

------------------------------------------------------------------------
Document No. and name 40 CFR part 86 reference
------------------------------------------------------------------------

* * * * * * *
ISO 15765-4:2001, Road Vehicles-- 86.010-18
Diagnostics on Controller Area
Network (CAN)--Part 4:
Requirements for emission-
related systems: December 2001.
------------------------------------------------------------------------

* * * * *
3. Section 86.007-17 is added to Subpart A to read as follows:

Sec. 86.007-17 On-board Diagnostics for engines used in applications
less than or equal to 14,000 pounds GVWR.

Section 86.007-17 includes text that specifies requirements that
differ from Sec. 86.005-17. Where a paragraph in Sec. 86.005-17 is
identical and applicable to Sec. 86.007-17, this may be indicated by
specifying the corresponding paragraph and the statement ``[Reserved].
For guidance see Sec. 86.005-17.''
(a)(1) [Reserved]. For guidance see Sec. 86.005-17.
(a)(2) An OBD system demonstrated to fully meet the requirements in
Sec. 86.1806-07 may be used to meet the requirements of this section,
provided that the Administrator finds that a manufacturer's decision to
use the flexibility in this paragraph (a)(2) is based on good
engineering judgment.
(b) introductory text and (b)(1)(i) [Reserved]. For guidance see
Sec. 86.005-17.
(b)(1)(ii) Diesel.
(A) If equipped, catalyst deterioration or malfunction before it
results in exhaust NO_X emissions exceeding either: 1.75
times the applicable NO_X standard for engines certified to a
NO_X FEL greater than 0.50 g/bhp-hr; or, the applicable
NO_X FEL+0.5 g/bhp-hr for engines certified to a
NO_X FEL less than or equal to 0.50 g/bhp-hr. This
requirement applies only to reduction catalysts; monitoring of
oxidation catalysts is not required. This monitoring need not be done
if the manufacturer can demonstrate that deterioration or malfunction
of the system will not result in exceedance of the threshold.
(b)(1)(ii)(B) and (b)(2) [Reserved]. For guidance see Sec. 86.005-17.
(b)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of
aftertreatment devices.
(A) Otto-cycle. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NO_X standard for
engines certified to a NO_X FEL greater than 0.50 g/bhp-hr;
or, the applicable NO_X FEL+0.5 g/bhp-hr for engines
certified to a NO_X FEL less than or equal to 0.50 g/bhp-hr;
or, 2.5 times the applicable NMHC standard.
(ii) Oxygen sensors and air-fuel ratio sensors upstream of
aftertreatment devices.
(A) Otto-cycle. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NO_X standard for
engines certified to a NO_X FEL greater than 0.50 g/bhp-hr;
or, the applicable NO_X FEL+0.5 g/bhp-hr for engines
certified to a NO_X FEL less than or equal to .50 g/bhp-hr;
or, 2.5 times the applicable NMHC standard; or, 2.5 times the
applicable CO standard.
(iii) NO_X sensors.
(A) Otto-cycle. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NO_X standard for
engines certified to a NO_X FEL greater than 0.50 g/bhp-hr;
or, the applicable NO_X FEL+0.5 g/bhp-hr for engines
certified to a NO_X FEL less than or equal to 0.50 g/bhp-hr.
(b)(4) [Reserved]. For guidance see Sec. 86.005--17.
(b)(5) Other emission control systems and components.
(i) Otto-cycle. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas recirculation
(EGR) system, if equipped, the secondary air system, if equipped, and
the fuel control system, singularly resulting in exhaust emissions
exceeding 1.5 times the applicable emission standard or FEL for NMHC,
NO_X or CO. For engines equipped with a secondary air system,
a functional check, as described in Sec. 86.005-17(b)(6), may satisfy
the requirements of this paragraph (b)(5) provided the manufacturer can
demonstrate that deterioration of the flow distribution system is
unlikely. This demonstration is subject to Administrator approval and,
if the demonstration and associated functional check are approved, the
diagnostic system must indicate a malfunction when some degree of
secondary airflow is not detectable in the exhaust system during the
check. For engines equipped with positive crankcase ventilation (PCV),
monitoring of the PCV system is not necessary provided the manufacturer
can demonstrate to the Administrator's satisfaction that the PCV system
is unlikely to fail.
(ii) Diesel. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas

[[Page 3287]]

recirculation (EGR) system, if equipped, and the fuel control system,
singularly resulting in exhaust emissions exceeding any of the
following levels: The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr
PM, whichever is higher; or, 1.75 times the applicable NO_X
standard for engines certified to a NO_X FEL greater than
0.50 g/bhp-hr; or, the applicable NO_X FEL+0.5 g/bhp-hr for
engines certified to a NO_X FEL less than or equal to 0.50 g/
bhp-hr; or, 2.5 times the applicable NMHC standard; or, 2.5 times the
applicable CO standard. A functional check, as described in Sec.
86.005-17(b)(6), may satisfy the requirements of this paragraph (b)(5)
provided the manufacturer can demonstrate that a malfunction would not
cause emissions to exceed the applicable levels. This demonstration is
subject to Administrator approval. For engines equipped with crankcase
ventilation (CV), monitoring of the CV system is not necessary provided
the manufacturer can demonstrate to the Administrator's satisfaction
that the CV system is unlikely to fail.
(b)(6) [Reserved]. For guidance see Sec. 86.005-17.
(b)(7) Performance of OBD functions. Any sensor or other component
deterioration or malfunction which renders that sensor or component
incapable of performing its function as part of the OBD system must be
detected and identified on engines so equipped.
(c), (d), (e), (f), (g), and (h)(1)(i) through (h)(1)(iv)
[Reserved]. For guidance see Sec. 86.005-17.
(h)(1)(v) All acronyms, definitions and abbreviations shall be
formatted according to SAE J1930 ``Electrical/Electronic Systems
Diagnostic Terms, Definitions, Abbreviations, and Acronyms Equivalent
to ISO/TR 15031-2: April 30, 2002'', (Revised, April 2002), or SAE J2403,
``Medium/Heavy-Duty E/E Systems Diagnosis Nomenclature: August 2004.''
(h)(1)(vi) through (h)(3) [Reserved]. For guidance see Sec. 86.005-17.
(i) Deficiencies and alternative fueled engines. Upon application
by the manufacturer, the Administrator may accept an OBD system as
compliant even though specific requirements are not fully met. Such
compliances without meeting specific requirements, or deficiencies,
will be granted only if compliance would be infeasible or unreasonable
considering such factors as, but not limited to: Technical feasibility
of the given monitor and lead time and production cycles including
phase-in or phase-out of engines or vehicle designs and programmed
upgrades of computers. Unmet requirements should not be carried over
from the previous model year except where unreasonable hardware or
software modifications would be necessary to correct the deficiency,
and the manufacturer has demonstrated an acceptable level of effort
toward compliance as determined by the Administrator. Furthermore, EPA
will not accept any deficiency requests that include the complete lack
of a major diagnostic monitor (``major'' diagnostic monitors being
those for exhaust aftertreatment devices, oxygen sensor, air-fuel ratio
sensor, NO_X sensor, engine misfire, evaporative leaks, and
diesel EGR, if equipped), with the possible exception of the special
provisions for alternative fueled engines. For alternative fueled
heavy-duty engines (e.g. natural gas, liquefied petroleum gas,
methanol, ethanol), manufacturers may request the Administrator to
waive specific monitoring requirements of this section for which
monitoring may not be reliable with respect to the use of the
alternative fuel. At a minimum, alternative fuel engines must be
equipped with an OBD system meeting OBD requirements to the extent
feasible as approved by the Administrator.
(j) California OBDII compliance option. For heavy-duty engines used
in applications weighing 14,000 pounds GVWR or less, demonstration of
compliance with California OBD II requirements (Title 13 California
Code of Regulations section 1968.2 (13 CCR 1968.2)), as modified and
released on August 11, 2006, shall satisfy the requirements of this
section, except that compliance with 13 CCR 1968.2(e)(4.2.2)(C),
pertaining to 0.02 inch evaporative leak detection, and 13 CCR
1968.2(d)(1.4), pertaining to tampering protection, are not required to
satisfy the requirements of this section. Also, the deficiency
provisions of 13 CCR 1968.2(k) do not apply. The deficiency provisions
of paragraph (i) of this section and the evaporative leak detection
requirement of Sec. 86.005-17(b)(4) apply to manufacturers selecting
this paragraph for demonstrating compliance. In addition, demonstration
of compliance with 13 CCR 1968.2(e)(15.2.1)(C), to the extent it
applies to the verification of proper alignment between the camshaft and
crankshaft, applies only to vehicles equipped with variable valve timing.
(k) [Reserved]. For guidance see Sec. 86.005-17.
4. Section 86.007-30 is added to Subpart A to read as follows:
Section 86.007-30 includes text that specifies requirements that
differ from Sec. Sec. 86.094-30, 86.095-30, 86.096-30, 86.098-30,
86.001-30 or 86.004-30. Where a paragraph in Sec. 86.094-30, Sec.
86.095-30, Sec. 86.096-30, Sec. 86.098-30, Sec. 86.001-30 or Sec.
86.004-30 is identical and applicable to Sec. 86.007-30, this may be
indicated by specifying the corresponding paragraph and the statement
``[Reserved]. For guidance see Sec. 86.094-30.'' or ``[Reserved]. For
guidance see Sec. 86.095-30.'' or ``[Reserved]. For guidance see Sec.
86.096-30.'' or ``[Reserved]. For guidance see Sec. 86.098-30.'' or
``[Reserved]. For guidance see Sec. 86.001-30.'' or ``[Reserved]. For
guidance see 86.004-30.''

Sec. 86.007-30 Certification.

(a)(1) and (a)(2) [Reserved]. For guidance see Sec. 86.094-30.
(a)(3)(i) through (a)(4)(ii) [Reserved]. For guidance see Sec.
86.004-30.
(a)(4)(iii) introductory text through (a)(4)(iii)(C) [Reserved].
For guidance see Sec. 86.094-30.
(a)(4)(iv) introductory text [Reserved]. For guidance see Sec.
86.095-30.
(a)(4)(iv)(A)-(a)(9) [Reserved]. For guidance see Sec. 86.094-30.
(a)(10) and (a)(11) [Reserved]. For guidance see Sec. 86.004-30.
(a)(12) [Reserved]. For guidance see Sec. 86.094-30.
(a)(13) [Reserved]. For guidance see Sec. 86.095-30.
(a)(14) [Reserved]. For guidance see Sec. 86.094-30.
(a) (15)-(18) [Reserved]. For guidance see Sec. 86.096-30.
(a)(19) [Reserved]. For guidance see Sec. 86.098-30.
(a)(20) [Reserved]. For guidance see Sec. 86.001-30.
(a)(21) [Reserved]. For guidance see Sec. 86.004-30.
(b)(1) introductory text through (b)(1)(ii)(A) [Reserved]. For
guidance see Sec. 86.094-30.
(b)(1)(ii)(B) [Reserved]. For guidance see Sec. 86.004-30.
(b)(1)(ii)(C) [Reserved]. For guidance see Sec. 86.094-30.
(b)(1)(ii)(D) [Reserved]. For guidance see Sec. 86.004-30.
(b)(1)(iii) and (b)(1)(iv) [Reserved]. For guidance see Sec. 86.094-30.
(b)(2) [Reserved]. For guidance see Sec. 86.098-30.
(b)(3)-(b)(4)(i) [Reserved]. For guidance see Sec. 86.094-30.
(b)(4)(ii) introductory text [Reserved]. For guidance see Sec.
86.098-30.
(b)(4)(ii)(A) [Reserved]. For guidance see Sec. 86.094-30.
(b)(4)(ii)(B)-(b)(4)(iv) [Reserved]. For guidance see Sec. 86.098-30.
(b)(5)-(e) [Reserved]. For guidance see Sec. 86.094-30.
(f) introductory text through (f)(1)(i) [Reserved]. For guidance
see Sec. 86.004-30.

[[Page 3288]]

(f)(1)(ii) Diesel.
(A) If monitored for emissions performance--a catalyst is replaced
with a deteriorated or defective catalyst, or an electronic simulation
of such, resulting in exhaust emissions exceeding 1.75 times the
applicable NO_X standard for engines certified to a
NO_X FEL greater than 0.50 g/bhp-hr; or, the applicable
NO_X FEL+0.5 g/bhp-hr for engines certified to a
NO_X FEL less than or equal to 0.50 g/bhp-hr. This
requirement applies only to reduction catalysts.
(B) If monitored for performance--a particulate trap is replaced
with a trap that has catastrophically failed, or an electronic
simulation of such.
(f)(2) [Reserved]. For guidance see Sec. 86.004-30.
(f)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of
aftertreatment devices.
(A) Otto-cycle. If so equipped, any oxygen sensor or air-fuel ratio
sensor located downstream of aftertreatment devices is replaced with a
deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If so equipped, any oxygen sensor or air-fuel ratio
sensor located downstream of aftertreatment devices is replaced with a
deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NO_X standard for
engines certified to a NO_X FEL greater than 0.50 g/bhp-hr;
or, the applicable NO_X FEL+0.5 g/bhp-hr for engines
certified to a NO_X FEL less than or equal to 0.50 g/bhp-hr;
or, 2.5 times the applicable NMHC standard.
(ii) Oxygen sensors and air-fuel ratio sensors upstream of
aftertreatment devices.
(A) Otto-cycle. If so equipped, any oxygen sensor or air-fuel ratio
sensor located upstream of aftertreatment devices is replaced with a
deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If so equipped, any oxygen sensor or air-fuel ratio
sensor located upstream of aftertreatment devices is replaced with a
deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NO_X standard for
engines certified to a NO_X FEL greater than 0.50 g/bhp-hr;
or, the applicable NO_X FEL+0.5 g/bhp-hr for engines
certified to a NO_X FEL less than or equal to 0.50 g/bhp-hr;
or, 2.5 times the applicable NMHC standard; or, 2.5 times the
applicable CO standard.
(iii) NO_X sensors.
(A) Otto-cycle. If so equipped, any NO_X sensor is
replaced with a deteriorated or defective sensor, or an electronic
simulation of such, resulting in exhaust emissions exceeding 1.5 times
the applicable standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If so equipped, any NO_X sensor is replaced
with a deteriorated or defective sensor, or an electronic simulation of
such, resulting in exhaust emissions exceeding any of the following
levels: the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM,
whichever is higher; or, 1.75 times the applicable NO_X
standard for engines certified to a NO_X FEL greater than
0.50 g/bhp-hr; or, the applicable NO_X FEL+0.5 g/bhp-hr for
engines certified to a NO_X FEL less than or equal to 0.50 g/
bhp-hr.
(f)(4) [Reserved]. For guidance see Sec. 86.004-30.
(f)(5)(i) Otto-cycle. A malfunction condition is induced in any
emission-related engine system or component, including but not
necessarily limited to, the exhaust gas recirculation (EGR) system, if
equipped, the secondary air system, if equipped, and the fuel control
system, singularly resulting in exhaust emissions exceeding 1.5 times
the applicable emission standard or FEL for NMHC, NO_X, or CO.
(ii) Diesel. A malfunction condition is induced in any emission-
related engine system or component, including but not necessarily
limited to, the exhaust gas recirculation (EGR) system, if equipped,
and the fuel control system, singularly resulting in exhaust emissions
exceeding any of the following levels: the applicable PM FEL+0.04 g/
bhp-hr or 0.05 g/bhp-hr PM, whichever is higher; or, 1.75 times the
applicable NO_X standard for engines certified to a
NO_X FEL greater than 0.50 g/bhp-hr; or, the applicable
NO_X FEL+0.5 g/bhp-hr for engines certified to a
NO_X FEL less than or equal to 0.50 g/bhp-hr; or, 2.5 times
the applicable NMHC standard; or, 2.5 times the applicable CO standard.
(f)(6) [Reserved]. For guidance see Sec. 86.004-30.
5. Section 86.010-2 is added to Subpart A to read as follows:

Sec. 86.010-2 Definitions.

The definitions of Sec. 86.004-2 continue to apply to 2004 and
later model year vehicles. The definitions listed in this section apply
beginning with the 2010 model year.
Drive cycle or driving cycle means operation that consists of
engine startup and engine shutoff during which a given onboard
diagnostic (OBD) monitor makes a diagnostic decision. A drive cycle
need not consist of all OBD monitors making a diagnostic decision
during the engine startup and engine shutoff cycle. An engine restart
following an engine shutoff that has been neither commanded by the
vehicle operator nor by the engine control strategy but caused by an
event such as an engine stall may be considered a new drive cycle or a
continuation of the existing drive cycle.
DTC means diagnostic trouble code.
Engine start as used in Sec. 86.010-18 means the point when the
engine reaches a speed 150 rpm below the normal, warmed-up idle speed
(as determined in the drive position for vehicles equipped with an
automatic transmission). For hybrid vehicles or for engines employing
alternative engine start hardware or strategies (e.g., integrated
starter and generators.), the manufacturer may use an alternative
definition for engine start (e.g., key-on) provided the alternative
definition is based on equivalence to an engine start for a
conventional vehicle.
Functional check, in the context of onboard diagnostics, means
verifying that a component and/or system that receives information from
a control computer responds properly to a command from the control computer.
Ignition cycle as used in Sec. 86.010-18 means a cycle that begins
with engine start, meets the engine start definition for at least two
seconds plus or minus one second, and ends with engine shutoff.
Limp-home operation as used in Sec. 86.010-18 means an operating
mode that an engine is designed to enter upon determining that normal
operation cannot be maintained. In general, limp-home operation implies
that a component or system is not operating properly or is believed to
be not operating properly.
Malfunction means the conditions have been met that require the
activation of an OBD malfunction indicator light and storage of a DTC.
MIL-on DTC means the diagnostic trouble code stored when an OBD
system has detected and confirmed that a malfunction exists (e.g.,
typically on the second drive cycle during which a given OBD monitor
has evaluated a system or component). Industry standards may refer to
this as a confirmed or an active DTC.

[[Page 3289]]

Pending DTC means the diagnostic trouble code stored upon the
detection of a potential malfunction.
Permanent DTC means a DTC that corresponds to a MIL-on DTC and is
stored in non-volatile random access memory (NVRAM). A permanent DTC
can only be erased by the OBD system itself and cannot be erased
through human interaction with the OBD system or any onboard computer.
Previous-MIL-on DTC means a DTC that corresponds to a MIL-on DTC
but is distinguished by representing a malfunction that the OBD system
has determined no longer exists but for which insufficient operation
has occurred to satisfy the DTC erasure provisions.
Potential malfunction means that conditions have been detected that
meet the OBD malfunction criteria but for which more drive cycles are
allowed to provide further evaluation prior to confirming that a
malfunction exists.
Rationality check, in the context of onboard diagnostics, means
verifying that a component that provides input to a control computer
provides an accurate input to the control computer while in the range
of normal operation and when compared to all other available information.
Similar conditions, in the context of onboard diagnostics, means
engine conditions having an engine speed within 375 rpm, load
conditions within 20 percent, and the same warm up status (i.e., cold
or hot). The manufacturer may use other definitions of similar
conditions based on comparable timeliness and reliability in detecting
similar engine operation.
6. Section 86.010-17 is added to Subpart A to read as follows:

Sec. 86.010-17 On-board Diagnostics for engines used in applications
less than or equal to 14,000 pounds GVWR.

Section 86.010-17 includes text that specifies requirements that
differ from Sec. 86.005-17 and Sec. 86.007-17. Where a paragraph in
Sec. 86.005-17 or Sec. 86.007-17 is identical and applicable to Sec.
86.010-17, this may be indicated by specifying the corresponding
paragraph and the statement ``[Reserved]. For guidance see Sec.
86.005-17.'' or ``[Reserved]. For guidance see Sec. 86.007-17.''
(a) General.
(1) All heavy-duty engines intended for use in a heavy-duty vehicle
weighing 14,000 pounds GVWR or less must be equipped with an on-board
diagnostic (OBD) system capable of monitoring all emission-related
engine systems or components during the applicable useful life. All
monitored systems and components must be evaluated periodically, but no
less frequently than once per applicable certification test cycle as
defined in Appendix I, paragraph (f), of this part, or similar trip as
approved by the Administrator.
(2) An OBD system demonstrated to fully meet the requirements in
Sec. 86.1806-10 may be used to meet the requirements of this section,
provided that the Administrator finds that a manufacturer's decision to
use the flexibility in this paragraph (a)(2) is based on good
engineering judgment.
(b) Introductory text and (b)(1)(i) [Reserved]. For guidance see
Sec. 86.005-17.
(b)(1)(ii) Diesel.
(A) If equipped, reduction catalyst deterioration or malfunction
before it results in exhaust NO_X emissions exceeding the
applicable NO_X FEL+0.3 g/bhp-hr. If equipped, oxidation
catalyst deterioration or malfunction before it results in exhaust NMHC
emissions exceeding 2.5 times the applicable NMHC standard. These
catalyst monitoring requirements need not be done if the manufacturer
can demonstrate that deterioration or malfunction of the system will
not result in exceedance of the threshold.
(B) If equipped, diesel particulate trap deterioration or
malfunction before it results in exhaust emissions exceeding any of the
following levels: The applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr
PM, whichever is higher; or, exhaust NMHC emissions exceeding 2.5 times
the applicable NMHC standard. Catastrophic failure of the particulate
trap must also be detected. In addition, the absence of the particulate
trap or the trapping substrate must be detected.
(b)(2) [Reserved]. For guidance see Sec. 86.005-17.
(b)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of
aftertreatment devices.
(A) Otto-cycle. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, the applicable NO_X FEL+0.3 g/bhp-hr; or, 2.5
times the applicable NMHC standard.
(ii) Oxygen sensors and air-fuel ratio sensors upstream of
aftertreatment devices.
(A) Otto-cycle. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is
higher; or, the applicable NO_X FEL+0.3 g/bhp-hr; or, 2.5
times the applicable NMHC standard; or, 2.5 times the applicable CO standard.
(iii) NOX sensors.
(A) Otto-cycle. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NO_X or CO.
(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, the applicable NO_X FEL+0.3 g/bhp-hr.
(b)(4) [Reserved]. For guidance see Sec. 86.005-17.
(b)(5) Other emission control systems and components.
(i) Otto-cycle. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas recirculation
(EGR) system, if equipped, the secondary air system, if equipped, and
the fuel control system, singularly resulting in exhaust emissions
exceeding 1.5 times the applicable emission standard or FEL for NMHC,
NO_X or CO. For engines equipped with a secondary air system,
a functional check, as described in Sec. 86.005-17(b)(6), may satisfy
the requirements of this paragraph (b)(5) provided the manufacturer can
demonstrate that deterioration of the flow distribution system is
unlikely. This demonstration is subject to Administrator approval and,
if the demonstration and associated functional check are approved, the
diagnostic system must indicate a malfunction when some degree of
secondary airflow is not detectable in the exhaust system during the
check. For engines equipped with positive crankcase ventilation (PCV),
monitoring of the PCV system is not necessary provided the manufacturer
can demonstrate to the Administrator's satisfaction that the PCV system
is unlikely to fail.
(ii) Diesel. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas recirculation
(EGR) system, if equipped, and the fuel control system, singularly
resulting in exhaust emissions

[[Page 3290]]

exceeding any of the following levels: the applicable PM FEL+0.02 g/
bhp-hr or 0.03 g/bhp-hr PM, whichever is higher; or, the applicable
NO_X FEL+0.3 g/bhp-hr; or, 2.5x the applicable NMHC standard;
or, 2.5x the applicable CO standard. A functional check, as described
in Sec. 86.005-17(b)(6), may satisfy the requirements of this
paragraph (b)(5) provided the manufacturer can demonstrate that a
malfunction would not cause emissions to exceed the applicable levels.
This demonstration is subject to Administrator approval. For engines
equipped with crankcase ventilation (CV), monitoring of the CV system
is not necessary provided the manufacturer can demonstrate to the
Administrator's satisfaction that the CV system is unlikely to fail.
(b)(6) [Reserved]. For guidance see Sec. 86.005-17.
(b)(7) [Reserved]. For guidance see Sec. 86.007-17.
(c) [Reserved]. For guidance see Sec. 86.005-17.
(d) MIL illumination.
(1) The MIL must illuminate and remain illuminated when any of the
conditions specified in paragraph (b) of this section are detected and
verified, or whenever the engine control enters a default or secondary
mode of operation considered abnormal for the given engine operating
conditions. The MIL must blink once per second under any period of
operation during which engine misfire is occurring and catalyst damage
is imminent. If such misfire is detected again during the following
driving cycle (i.e., operation consisting of, at a minimum, engine
start-up and engine shut-off) or the next driving cycle in which
similar conditions are encountered, the MIL must maintain a steady
illumination when the misfire is not occurring and then remain
illuminated until the MIL extinguishing criteria of this section are
satisfied. The MIL must also illuminate when the vehicle's ignition is
in the ``key-on'' position before engine starting or cranking and
extinguish after engine starting if no malfunction has previously been
detected. If a fuel system or engine misfire malfunction has previously
been detected, the MIL may be extinguished if the malfunction does not
reoccur during three subsequent sequential trips during which similar
conditions are encountered and no new malfunctions have been detected.
Similar conditions are defined as engine speed within 375 rpm, engine
load within 20 percent, and engine warm-up status equivalent to that
under which the malfunction was first detected. If any malfunction
other than a fuel system or engine misfire malfunction has been
detected, the MIL may be extinguished if the malfunction does not
reoccur during three subsequent sequential trips during which the
monitoring system responsible for illuminating the MIL functions
without detecting the malfunction, and no new malfunctions have been
detected. Upon Administrator approval, statistical MIL illumination
protocols may be employed, provided they result in comparable
timeliness in detecting a malfunction and evaluating system performance,
i.e., three to six driving cycles would be considered acceptable.
(2) Drive cycle or driving cycle, in the context of this section
Sec. 86.010-17, the definition for drive cycle or driving cycle given
in Sec. 86.010-2 is enhanced. A drive cycle means an OBD trip that
consists of engine startup and engine shutoff and includes the period
of engine off time up to the next engine startup. For vehicles that
employ engine shutoff strategies (e.g., engine shutoff at idle), the
manufacturer may use an alternative definition for drive cycle (e.g.,
key-on followed by key-off). Any alternative definition must be based
on equivalence to engine startup and engine shutoff signaling the
beginning and ending of a single driving event for a conventional
vehicle. For applications that span 14,000 pounds GVWR, the
manufacturer may use the drive cycle definition of Sec. 86.010-18 in
lieu of the definition in this paragraph.
(e), (f), (g), and (h)(1)(i) through (h)(1)(iv) [Reserved]. For
guidance see Sec. 86.005-17.
(h)(1)(v) [Reserved]. For guidance see Sec. 86.007-17.
(h)(1)(vi) through (h)(3) [Reserved]. For guidance see Sec. 86.005-17.
(i) and (j) [Reserved]. For guidance see Sec. 86.007-17.
(k) [Reserved.]
7. Section 86.010-18 is added to Subpart A to read as follows:

Sec. 86.010-18 On-board Diagnostics for engines used in applications
greater than 14,000 pounds GVWR.

(a) General. According to the implementation schedule shown in
paragraph (o) of this section, heavy-duty engines intended for use in a
heavy-duty vehicle weighing more than 14,000 pounds GVWR must be
equipped with an on-board diagnostic (OBD) system capable of monitoring
all emission-related engine systems or components during the life of
the engine. The OBD system is required to detect all malfunctions
specified in paragraphs (g), (h), and (i) of this section although the
OBD system is not required to use a unique monitor to detect each of
those malfunctions.
(1) When the OBD system detects a malfunction, it must store a
pending, a MIL-on, or a previous-MIL-on diagnostic trouble code (DTC)
in the onboard computer's memory. A malfunction indicator light (MIL)
must also be activated as specified in paragraph (b) of this section.
(2) The OBD system must be equipped with a data link connector to
provide access to the stored DTCs as specified in paragraph (k)(2) of
this section.
(3) The OBD system cannot be programmed or otherwise designed to
deactivate based on age and/or mileage. This requirement does not alter
existing law and enforcement practice regarding a manufacturer's
liability for an engine beyond its regulatory useful life, except where
an engine has been programmed or otherwise designed so that an OBD
system deactivates based on age and/or mileage of the engine.
(4) Drive cycle or driving cycle, in the context of this section,
the definition for drive cycle or driving cycle given in Sec. 86.010-2
is enhanced. A drive cycle means an OBD trip that meets any of the
conditions of paragraphs (a)(4)(i) through (a)(4)(iv) of this section.
Further, for OBD monitors that run during engine-off conditions, the
period of engine-off time following engine shutoff and up to the next
engine start may be considered part of the drive cycle for the
conditions of paragraphs (a)(4)(i) and (a)(4)(iv) of this section. For
engines/vehicles that employ engine shutoff OBD monitoring strategies
that do not require the vehicle operator to restart the engine to
continue vehicle operation (e.g., a hybrid bus with engine shutoff at
idle), the manufacturer may use an alternative definition for drive
cycle (e.g., key-on followed by key-off). Any alternative definition
must be based on equivalence to engine startup and engine shutoff
signaling the beginning and ending of a single driving event for a
conventional vehicle. For engines that are not likely to be routinely
operated for long continuous periods of time, a manufacturer may also
request approval to use an alternative definition for drive cycle
(e.g., solely based on engine start and engine shutoff without regard
to four hours of continuous engine-on time). Administrator approval of
the alternative definition will be based on manufacturer-submitted data
and/or information demonstrating the typical usage, operating habits,
and/or driving patterns of these vehicles.
(i) Begins with engine start and ends with engine shutoff;

[[Page 3291]]

(ii) Begins with engine start and ends after four hours of
continuous engine-on operation;
(iii) Begins at the end of the previous four hours of continuous
engine-on operation and ends after four hours of continuous engine-on
operation; or
(iv) Begins at the end of the previous four hours of continuous
engine-on operation and ends with engine shutoff.
(b) Malfunction indicator light (MIL) and Diagnostic Trouble Codes
(DTC). The OBD system must incorporate a malfunction indicator light
(MIL) or equivalent and must store specific types of diagnostic trouble
codes (DTC).
(1) MIL specifications.
(i) [Reserved.]
(ii) The OBD system must activate the MIL when the ignition is in
the key-on/engine-off position before engine cranking to indicate that
the MIL is functional. The MIL shall be activated continuously during
this functional check for a minimum of 5 seconds. During this MIL key-
on functional check, the data stream value (see paragraph (k)(4)(ii) of
this section) for MIL status must indicate ``commanded off'' unless the
OBD system has detected a malfunction and has stored a MIL-on DTC. This
MIL key-on functional check is not required during vehicle operation in
the key-on/engine-off position subsequent to the initial engine
cranking of an ignition cycle (e.g., due to an engine stall or other
non-commanded engine shutoff).
(iii) As an option, the MIL may be used to indicate readiness
status (see paragraph (k)(4)(i) of this section) in a standardized
format in the key-on/engine-off position.
(iv) A manufacturer may also use the MIL to indicate which, if any,
DTCs are currently stored (e.g., to ``blink'' the stored DTCs). Such
use must not activate unintentionally during routine driver operation.
(v) [Reserved.]
(2) MIL activation and DTC storage protocol.
(i) Within 10 seconds of detecting a potential malfunction, the OBD
system must store a pending DTC that identifies the potential malfunction.
(ii) If the potential malfunction is again detected before the end
of the next drive cycle during which monitoring occurs (i.e., the
potential malfunction has been confirmed as a malfunction), then within
10 seconds of such detection the OBD system must activate the MIL
continuously and store a MIL-on DTC. If the potential malfunction is
not detected before the end of the next drive cycle during which
monitoring occurs (i.e., there is no indication of the malfunction at
any time during the drive cycle), the corresponding pending DTC should
be erased at the end of the drive cycle. Similarly, if a malfunction is
detected for the first time and confirmed on a given drive cycle
without need for further evaluation, then within 10 seconds of such
detection the OBD system must activate the MIL continuously and store a
MIL-on DTC.
(iii) A manufacturer may request Administrator approval to employ
alternative statistical MIL activation and DTC storage protocols to
those specified in paragraphs (b)(2)(i) and (b)(2)(ii) of this section.
Approval will depend upon the manufacturer providing data and/or
engineering evaluations that demonstrate that the alternative protocols
can evaluate system performance and detect malfunctions in a manner
that is equally effective and timely. Strategies requiring on average
more than six drive cycles for MIL activation will not be accepted.
(iv) The OBD system must store a ``freeze frame'' of the operating
conditions (as defined in paragraph (k)(4)(iii) of this section)
present upon detecting a malfunction or a potential malfunction. In the
event that a pending DTC has matured to a MIL-on DTC, the manufacturer
shall either retain the currently stored freeze frame conditions or
replace the stored freeze frame with freeze frame conditions regarding
the MIL-on DTC. Any freeze frame stored in conjunction with any pending
DTC or MIL-on DTC should be erased upon erasure of the corresponding DTC.
(v) If the engine enters a limp-home mode of operation that can
affect emissions or the performance of the OBD system, or in the event
of a malfunction of an onboard computer(s) itself that can affect the
performance of the OBD system, the OBD system must activate the MIL and
store a MIL-on DTC within 10 seconds to inform the vehicle operator. If
the limp-home mode of operation is recoverable (i.e., operation
automatically returns to normal at the beginning of the following
ignition cycle), the OBD system may wait to activate the MIL and store
the MIL-on DTC if the limp-home mode of operation is again entered
before the end of the next ignition cycle rather than activating the
MIL within 10 seconds on the first drive cycle during which the limp-
home mode of operation is entered.
(vi) Before the end of an ignition cycle, the OBD system must store
a permanent DTC(s) that corresponds to any stored MIL-on DTC(s).
(3) MIL deactivation and DTC erasure protocol.
(i) Deactivating the MIL. Except as otherwise provided for in
paragraph (g)(6)(iv)(B) of this section for empty reductant tanks, and
paragraphs (h)(1)(iv)(F), (h)(2)(viii), and (h)(7)(iv)(B) of this
section for gasoline fuel system, misfire, and evaporative system
malfunctions, once the MIL has been activated, it may be deactivated
after three subsequent sequential drive cycles during which the
monitoring system responsible for activating the MIL functions and the
previously detected malfunction is no longer present and provided no
other malfunction has been detected that would independently activate
the MIL according to the requirements outlined in paragraph (b)(2) of
this section.
(ii) Erasing a MIL-on DTC. The OBD system may erase a MIL-on DTC if
the identified malfunction has not again been detected in at least 40
engine warm up cycles and the MIL is presently not activated for that
malfunction. The OBD system may also erase a MIL-on DTC upon
deactivating the MIL according to paragraph (b)(3)(i) of this section
provided a previous-MIL-on DTC is stored upon erasure of the MIL-on
DTC. The OBD system may erase a previous-MIL-on DTC if the identified
malfunction has not again been detected in at least 40 engine warm up
cycles and the MIL is presently not activated for that malfunction.
(iii) Erasing a permanent DTC. The OBD system can erase a permanent
DTC only if either of the following conditions occur:
(A) The OBD system itself determines that the malfunction that
caused the corresponding MIL-on DTC to be stored is no longer present
and is not commanding activation of the MIL, concurrent with the
requirements of paragraph (b)(3)(i) of this section.
(B) Subsequent to erasing the DTC information from the on-board
computer (i.e., through the use of a scan tool or a battery
disconnect), the OBD monitor for the malfunction that caused the
permanent DTC to be stored has executed the minimum number of
monitoring events necessary for MIL activation and has determined that
the malfunction is no longer present.
(4) Exceptions to MIL and DTC requirements.
(i) If a limp-home mode of operation causes an overt indication
(e.g., activation of a red engine shut-down warning light) such that
the driver is certain to respond and have the problem corrected, a
manufacturer may choose not to activate the MIL as required by
paragraph (b)(2)(v) of this section. Additionally, if an auxiliary
emission control device has been properly

[[Page 3292]]

activated as approved by the Administrator, a manufacturer may choose
not to activate the MIL.
(ii) For gasoline engines, a manufacturer may choose to meet the
MIL and DTC requirements in Sec. 86.010-17 in lieu of meeting the
requirements of paragraph (b) of Sec. 86.010-18.
(a) Monitoring conditions. The OBD system must monitor and detect
the malfunctions specified in paragraphs (g), (h), and (i) of this
section under the following general monitoring conditions. The more
specific monitoring conditions of paragraph (d) of this section are
sometimes required according to the provisions of paragraphs (g), (h),
and (i) of this section.
(1) As specifically provided for in paragraphs (g), (h), and (i) of
this section, the monitoring conditions for detecting malfunctions must
be technically necessary to ensure robust detection of malfunctions
(e.g., avoid false passes and false indications of malfunctions);
designed to ensure monitoring will occur under conditions that may
reasonably be expected to be encountered in normal vehicle operation
and normal vehicle use; and, designed to ensure monitoring will occur
during the FTP transient test cycle contained in Appendix I paragraph
(f), of this part, or similar drive cycle as approved by the Administrator.
(2) Monitoring must occur at least once per drive cycle in which
the monitoring conditions are met.
(3) Manufacturers may request approval to define monitoring
conditions that are not encountered during the FTP cycle as required in
paragraph (c)(1) of this section. In evaluating the manufacturer's
request, the Administrator will consider the degree to which the
requirement to run during the FTP transient cycle restricts monitoring
during in-use operation, the technical necessity for defining
monitoring conditions that are not encountered during the FTP cycle,
data and/or an engineering evaluation submitted by the manufacturer
that demonstrate that the component/system does not normally function
during the FTP, whether monitoring is otherwise not feasible during the
FTP cycle, and/or the ability of the manufacturer to demonstrate that
the monitoring conditions satisfy the minimum acceptable in-use monitor
performance ratio requirement as defined in paragraph (d) of this section.
(d) In-use performance tracking. As specifically required in
paragraphs (g), (h), and (i) of this section, the OBD system must
monitor and detect the malfunctions specified in paragraphs (g), (h),
and (i) of this section according to the criteria of this paragraph
(d). The OBD system is not required to track and report in-use
performance for monitors other than those specifically identified in
paragraph (d)(1) of this section.
(1) The manufacturer must implement software algorithms in the OBD
system to individually track and report the in-use performance of the
following monitors, if equipped, in the standardized format specified
in paragraph (e) of this section: NMHC converting catalyst (paragraph
(g)(5) of this section); NO_X converting catalyst (paragraph
(g)(6) of this section); gasoline catalyst (paragraph (h)(6) of this
section); exhaust gas sensor (paragraph (g)(9) or (h)(8) of this
section); evaporative system (paragraph (h)(7) of this section); EGR
system (paragraph (g)(3) or (h)(3) of this section); VVT system
(paragraph (g)(10) or (h)(9) of this section); secondary air system
(paragraph (h)(5) of this section); DPF system (paragraph (g)(8) of
this section); boost pressure control system (paragraph (g)(4) of this
section); and, NO_X adsorber system (paragraph (g)(7) of this
section).
(i) The manufacturer shall not use the calculated ratio specified
in paragraph (d)(2) of this section or any other indication of monitor
frequency as a monitoring condition for a monitor (e.g., using a low
ratio to enable more frequent monitoring through diagnostic executive
priority or modification of other monitoring conditions, or using a
high ratio to enable less frequent monitoring).
(ii) [Reserved.]
(2) In-use performance ratio definition. For monitors required to
meet the requirements of paragraph (d) of this section, the performance
ratio must be calculated in accordance with the specifications of this
paragraph (d)(2).
(i) The numerator of the performance ratio is defined as the number
of times a vehicle has been operated such that all monitoring
conditions have been encountered that are necessary for the specific
monitor to detect a malfunction.
(ii) The denominator is defined as the number of times a vehicle
has been operated in accordance with the provisions of paragraph (d)(4)
of this section.
(iii) The performance ratio is defined as the numerator divided by
the denominator.
(3) Specifications for incrementing the numerator.
(i) Except as provided for in paragraph (d)(3)(v) of this paragraph
(d)(3), the numerator, when incremented, must be incremented by an
integer of one. The numerator shall not be incremented more than once
per drive cycle.
(ii) The numerator for a specific monitor must be incremented
within 10 seconds if and only if the following criteria are satisfied
on a single drive cycle:
(A) Every monitoring condition has been satisfied that is necessary
for the specific monitor to detect a malfunction and store a pending
DTC, including applicable enable criteria, presence or absence of
related DTCs, sufficient length of monitoring time, and diagnostic
executive priority assignments (e.g., diagnostic ``A'' must execute
prior to diagnostic ``B''). For the purpose of incrementing the
numerator, satisfying all the monitoring conditions necessary for a
monitor to determine that the monitor is not malfunctioning shall not,
by itself, be sufficient to meet this criteria.
(B) For monitors that require multiple stages or events in a single
drive cycle to detect a malfunction, every monitoring condition
necessary for all events to complete must be satisfied.
(C) For monitors that require intrusive operation of components to
detect a malfunction, a manufacturer must request approval of the
strategy used to determine that, had a malfunction been present, the
monitor would have detected the malfunction. Administrator approval of
the request will be based on the equivalence of the strategy to actual
intrusive operation and the ability of the strategy to determine
accurately if every monitoring condition was satisfied that was
necessary for the intrusive event to occur.
(D) For the secondary air system monitor, the criteria in
paragraphs (d)(3)(ii)(A) through (d)(3)(ii)(C) of this section are
satisfied during normal operation of the secondary air system.
Monitoring during intrusive operation of the secondary air system later
in the same drive cycle for the sole purpose of monitoring shall not,
by itself, be sufficient to meet these criteria.
(iii) For monitors that can generate results in a ``gray zone'' or
``non-detection zone'' (i.e., monitor results that indicate neither a
properly operating system nor a malfunctioning system) or in a ``non-
decision zone'' (e.g., monitors that increment and decrement counters
until a pass or fail threshold is reached), the numerator, in general,
shall not be incremented when the monitor indicates a result in the
``non-detection zone'' or prior to the monitor reaching a complete
decision. When necessary, the Administrator will consider data and/or
engineering analyses submitted by the manufacturer

[[Page 3293]]

demonstrating the expected frequency of results in the ``non-detection
zone'' and the ability of the monitor to determine accurately, had an
actual malfunction been present, whether or not the monitor would have
detected a malfunction instead of a result in the ``non-detection zone.''
(iv) For monitors that run or complete their evaluation with the
engine off, the numerator must be incremented either within 10 seconds
of the monitor completing its evaluation in the engine off state, or
during the first 10 seconds of engine start on the subsequent drive cycle.
(v) Manufacturers that use alternative statistical MIL activation
protocols as allowed in paragraph (b)(2)(iii) of this section for any
of the monitors requiring a numerator, are required to increment the
numerator(s) appropriately. The manufacturer may be required to provide
supporting data and/or engineering analyses demonstrating both the
equivalence of their incrementing approach to the incrementing
specified in this paragraph (d)(3) for monitors using the standard MIL
activation protocol.
(4) Specifications for incrementing the denominator.
(i) The denominator, when incremented, must be incremented by an
integer of one. The denominator shall not be incremented more than once
per drive cycle.
(ii) The denominator for each monitor must be incremented within 10
seconds if and only if the following criteria are satisfied on a single
drive cycle:
(A) Cumulative time since the start of the drive cycle is greater
than or equal to 600 seconds while at an elevation of less than 8,000
feet (2,400 meters) above sea level and at an ambient temperature of
greater than or equal to 20 degrees Fahrenheit (-7 C);
(B) Cumulative gasoline engine operation at or above 25 miles per
hour or diesel engine operation at or above 15% calculated load, either
of which occurs for greater than or equal to 300 seconds while at an
elevation of less than 8,000 feet (2,400 meters) above sea level and at
an ambient temperature of greater than or equal to 20 degrees
Fahrenheit (-7 C); and
(C) Continuous vehicle operation at idle (e.g., accelerator pedal
released by driver and vehicle speed less than or equal to one mile per
hour) for greater than or equal to 30 seconds while at an elevation of
less than 8,000 feet (2,400 meters) above sea level and at an ambient
temperature of greater than or equal to 20 degrees Fahrenheit (-7 C).
(iii) In addition to the requirements of paragraph (d)(4)(ii) of
this section, the evaporative system monitor denominator(s) may be
incremented if and only if:
(A) Cumulative time since the start of the drive cycle is greater
than or equal to 600 seconds while at an ambient temperature of greater
than or equal to 40 degrees Fahrenheit (4 C) but less than or equal to
95 degrees Fahrenheit (35 C); and,
(B) Engine cold start occurs with the engine coolant temperature
greater than or equal to 40 degrees Fahrenheit (4 C) but less than or
equal to 95 degrees Fahrenheit (35 C) and less than or equal to 12
degrees Fahrenheit (7 C) higher than the ambient temperature.
(iv) In addition to the requirements of paragraph (d)(4)(ii) of
this section, the denominator(s) for the following monitors may be
incremented if and only if the component or strategy is commanded
``on'' for a time greater than or equal to 10 seconds. For purposes of
determining this commanded ``on'' time, the OBD system shall not
include time during intrusive operation of any of the components or
strategies that occurs later in the same drive cycle for the sole
purpose of monitoring.
(A) Secondary air system (paragraph (h)(5) of this section).
(B) Cold start emission reduction strategy (paragraph (h)(4) of
this section).
(C) Components or systems that operate only at engine start-up
(e.g., glow plugs, intake air heaters) and are subject to monitoring
under ``other emission control systems'' (paragraph (i)(4) of this
section) or comprehensive component output components (paragraph
(i)(3)(iii) of this section).
(v) In addition to the requirements of paragraph (d)(4)(ii) of this
section, the denominator(s) for the following monitors of output
components (except those operated only at engine start-up and subject
to the requirements of paragraph (d)(4)(iv) of this section, may be
incremented if and only if the component is commanded to function
(e.g., commanded ``on'', ``opened'', ``closed'', ``locked'') on two or
more occasions during the drive cycle or for a time greater than or
equal to 10 seconds, whichever occurs first:
(A) Variable valve timing and/or control system (paragraph (g)(10)
or (h)(9) of this section).
(B) ``Other emission control systems'' (paragraph (i)(4) of this
section).
(C) Comprehensive component output component (paragraph (i)(3) of
this section) (e.g., turbocharger waste-gates, variable length manifold
runners).
(vi) For monitors of the following components, the manufacturer may
use alternative or additional criteria for incrementing the denominator
to that set forth in paragraph (d)(4)(ii) of this section. To do so,
the alternative criteria must be based on equivalence to the criteria
of paragraph (d)(4)(ii) of this section in measuring the frequency of
monitor operation relative to the amount of engine operation:
(A) Engine cooling system input components (paragraph (i)(1) of
this section).
(B) ``Other emission control systems'' (paragraph (i)(4) of this
section).
(C) Comprehensive component input components that require extended
monitoring evaluation (paragraph (i)(3) of this section) (e.g., stuck
fuel level sensor rationality).
(vii) For monitors of the following components or other emission
controls that experience infrequent regeneration events, the
manufacturer may use alternative or additional criteria for
incrementing the denominator to that set forth in paragraph (d)(4)(ii)
of this section. To do so, the alternative criteria must be based on
equivalence to the criteria of paragraph (d)(4)(ii) of this section in
measuring the frequency of monitor operation relative to the amount of
engine operation:
(A) Oxidation catalyst (paragraph (g)(5) of this section).
(B) DPF (paragraph (g)(8) of this section).
(viii) For hybrids that employ alternative engine start hardware or
strategies (e.g., integrated starter and generators), or alternative
fuel vehicles (e.g. dedicated, bi-fuel, or dual-fuel applications), the
manufacturer may use alternative criteria for incrementing the
denominator to that set forth in paragraph (d)(4)(ii) of this section.
In general, the Administrator will not approve alternative criteria for
those hybrids that employ engine shut off only at or near idle and/or
vehicle stop conditions. To use alternative criteria, the alternative
criteria must be based on the equivalence to the criteria of paragraph
(d)(4)(ii) of this section in measuring the amount of vehicle operation
relative to the measure of conventional vehicle operation.
(5) Disablement of numerators and denominators.
(i) Within 10 seconds of detecting a malfunction (i.e. a pending or
a MIL-on DTC has been stored) that disables a monitor for which the
monitoring conditions in paragraph (d) of this section must be met, the
OBD system must stop incrementing the numerator and denominator for any
monitor that may be disabled as a consequence of the detected
malfunction. Within 10 seconds of the time at which the malfunction is
no longer being detected

[[Page 3294]]

(e.g., the pending DTC is erased through OBD system self-clearing or
through a scan tool command), incrementing of all applicable numerators
and denominators must resume.
(ii) Within 10 seconds of the start of a power take-off unit (e.g.,
dump bed, snow plow blade, or aerial bucket, etc.) that disables a
monitor for which the monitoring conditions in paragraph (d) of this
section must be met, the OBD system must stop incrementing the
numerator and denominator for any monitor that may be disabled as a
consequence of power take-off operation. Within 10 seconds of the time
at which the power take-off operation ends, incrementing of all
applicable numerators and denominators must resume.
(iii) Within 10 seconds of detecting a malfunction (i.e., a pending
or a MIL-on DTC has been stored) of any component used to determine if
the criteria of paragraphs (d)(4)(ii) and (d)(4)(iii) of this section
are satisfied, the OBD system must stop incrementing all applicable
numerators and denominators. Within 10 seconds of the time at which the
malfunction is no longer being detected (e.g., the pending DTC is
erased through OBD system self-clearing or through a scan tool
command), incrementing of all applicable numerators and denominators
must resume.
(e) Standardized tracking and reporting of in-use monitor performance.
(1) General. For monitors required to track and report in-use
monitor performance according to paragraph (d) of this section, the
performance data must be tracked and reported in accordance with the
specifications in paragraphs (d)(2), (e), and (k)(5) of this section.
The OBD system must separately report an in-use monitor performance
numerator and denominator for each of the following components:
(i) For diesel engines, NMHC catalyst bank 1, NMHC catalyst bank 2,
NO_X catalyst bank 1, NO_X catalyst bank 2, exhaust
gas sensor bank 1, exhaust gas sensor bank 2, EGR/VVT system, DPF,
boost pressure control system, and NO_X adsorber. The OBD
system must also report a general denominator and an ignition cycle
counter in the standardized format specified in paragraphs (e)(5),
(e)(6), and (k)(5) of this section.
(ii) For gasoline engines, catalyst bank 1, catalyst bank 2,
exhaust gas sensor bank 1, exhaust gas sensor bank 2, evaporative leak
detection system, EGR/VVT system, and secondary air system. The OBD
system must also report a general denominator and an ignition cycle
counter in the standardized format specified in paragraphs (e)(5),
(e)(6), and (k)(5) of this section.
(iii) For specific components or systems that have multiple
monitors that are required to be reported under paragraphs (g) and (h)
of this section (e.g., exhaust gas sensor bank 1 may have multiple
monitors for sensor response or other sensor characteristics), the OBD
system must separately track numerators and denominators for each of
the specific monitors and report only the corresponding numerator and
denominator for the specific monitor that has the lowest numerical
ratio. If two or more specific monitors have identical ratios, the
corresponding numerator and denominator for the specific monitor that
has the highest denominator must be reported for the specific component.
(2) Numerator.
(i) The OBD system must report a separate numerator for each of the
applicable components listed in paragraph (e)(1) of this section.
(ii) The numerator(s) must be reported in accordance with the
specifications in paragraph (k)(5)(ii) of this section.
(3) Denominator.
(i) The OBD system must report a separate denominator for each of
the applicable components listed in paragraph (e)(1) of this section.
(ii) The denominator(s) must be reported in accordance with the
specifications in paragraph (k)(5)(ii) of this section.
(4) Monitor performance ratio. For purposes of determining which
corresponding numerator and denominator to report as required in
paragraph (e)(1)(iii) of this section, the ratio must be calculated in
accordance with the specifications in paragraph (k)(5)(iii) of this section.
(5) Ignition cycle counter.
(i) The ignition cycle counter is defined as a counter that
indicates the number of ignition cycles a vehicle has experienced
according to the specifications of paragraph (e)(5)(ii)(B) of this
section. The ignition cycle counter must be reported in accordance with
the specifications in paragraph (k)(5)(ii) of this section.
(ii) The ignition cycle counter must be incremented as follows:
(A) The ignition cycle counter, when incremented, must be
incremented by an integer of one. The ignition cycle counter shall not
be incremented more than once per ignition cycle.
(B) The ignition cycle counter must be incremented within 10
seconds if and only if the engine exceeds an engine speed of 50 to 150
rpm below the normal, warmed-up idle speed (as determined in the drive
position for engines paired with an automatic transmission) for at
least two seconds plus or minus one second.
(iii) Within 10 seconds of detecting a malfunction (i.e., a pending
or a MIL-on DTC has been stored) of any component used to determine if
the criteria in paragraph (e)(5)(ii)(B) of this section are satisfied
(i.e., engine speed or time of operation), the OBD system must stop
incrementing the ignition cycle counter. Incrementing of the ignition
cycle counter shall not be stopped for any other condition. Within 10
seconds of the time at which the malfunction is no longer being
detected (e.g., the pending DTC is erased through OBD system self-
clearing or through a scan tool command), incrementing of the ignition
cycle counter must resume.
(6) General denominator.
(i) The general denominator is defined as a measure of the number
of times an engine has been operated according to the specifications of
paragraph (e)(6)(ii)(B) of this section. The general denominator must
be reported in accordance with the specifications in paragraph
(k)(5)(ii) of this section.
(ii) The general denominator must be incremented as follows:
(A) The general denominator, when incremented, must be incremented
by an integer of one. The general denominator shall not be incremented
more than once per drive cycle.
(B) The general denominator must be incremented within 10 seconds
if and only if the criteria identified in paragraph (d)(4)(ii) of this
section are satisfied on a single drive cycle.
(C) Within 10 seconds of detecting a malfunction (i.e., a pending
or a MIL-on DTC has been stored) of any component used to determine if
the criteria in paragraph (d)(4)(ii) of this section are satisfied
(i.e., vehicle speed/load, ambient temperature, elevation, idle
operation, or time of operation), the OBD system must stop incrementing
the general denominator. Incrementing of the general denominator shall
not be stopped for any other condition (e.g., the disablement criteria
in paragraphs (d)(5)(i) and (d)(5)(ii) of this section shall not
disable the general denominator). Within 10 seconds of the time at
which the malfunction is no longer being detected (e.g., the pending
DTC is erased through OBD system self-clearing or through a scan tool
command), incrementing of the general denominator must resume.
(f) Malfunction criteria determination.
(1) In determining the malfunction criteria for the diesel engine
monitors required under paragraphs (g) and (i) of

[[Page 3295]]

this section that are required to indicate a malfunction before
emissions exceed an emission threshold based on any applicable
standard, the manufacturer must:
(i) Use the emission test cycle and standard (i.e., the transient
FTP or the supplemental emissions test (SET)) determined by the
manufacturer to be more stringent (i.e., to result in higher emissions
with the same level of monitored component malfunction). The
manufacturer must use data and/or engineering analysis to determine the
test cycle and standard that is more stringent.
(ii) Identify in the certification documentation required under
paragraph (m) of this section, the test cycle and standard determined
by the manufacturer to be the most stringent for each applicable monitor.
(iii) If the Administrator reasonably believes that a manufacturer
has determined incorrectly the test cycle and standard that is most
stringent, the manufacturer must be able to provide emission data and/
or engineering analysis supporting their choice of test cycle and standard.
(2) On engines equipped with emission controls that experience
infrequent regeneration events, a manufacturer must adjust the emission
test results that are used to determine the malfunction criteria for
monitors that are required to indicate a malfunction before emissions
exceed a certain emission threshold. For each such monitor, the
manufacturer must adjust the emission result as done in accordance with
the provisions of section 86.004-28(i) with the component for which the
malfunction criteria are being established having been deteriorated to
the malfunction threshold. The adjusted emission value must be used for
purposes of determining whether or not the applicable emission
threshold is exceeded.
(i) For purposes of this paragraph (f)(2) of this section,
regeneration means an event, by design, during which emissions levels
change while the emission control performance is being restored.
(ii) For purposes of this paragraph (f)(2) of this section,
infrequent means having an expected frequency of less than once per
transient FTP cycle.
(3) For gasoline engines, rather than meeting the malfunction
criteria specified under paragraphs (h) and (i) of this section, the
manufacturer may request approval to use an OBD system certified to the
requirements of Sec. 86.010-17. To do so, the manufacturer must
demonstrate use of good engineering judgment in determining equivalent
malfunction detection criteria to those required in this section.
(g) OBD monitoring requirements for diesel-fueled/compression-
ignition engines. The following table shows the thresholds at which
point certain components or systems, as specified in this paragraph
(g), are considered malfunctioning.

Table 1.--OBD Emissions Thresholds for Diesel-Fueled/Compression-Ignition Engines Meant for Placement in Applications Greater Than 14,000 Pounds GVWR (g/
bhp-hr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Component Sec. 86.010-18 reference NMHC CO NOX PM
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMHC catalyst system................ (g)(5)............................ 2.5x................. .................... .................... ...........
NOX aftertreatment system........... (g)(6), (g)(7).................... ..................... .................... +0.3................ ...........
Diesel particulate filter (DPF) (g)(8)............................ 2.5x................. .................... .................... 0.05/+0.04
system.
Air-fuel ratio sensors upstream of (g)(9)............................ 2.5x................. 2.5x................ +0.3................ 0.03/+0.02
aftertreatment devices.
Air-fuel ratio sensors downstream of (g)(9)............................ 2.5x................. .................... +0.3................ 0.05/+0.04
aftertreatment devices.
NOX sensors......................... (g)(9)............................ ..................... .................... +0.3................ 0.05/+0.04
``Other monitors'' with emissions (g)(1), (g)(3), (g)(4), (g)(10)... 2.5x................. 2.5x................ +0.3................ 0.03/+0.02
thresholds.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: FEL=Family Emissions Limit; 2.5x std means a multiple of 2.5 times the applicable emissions standard; +0.3 means the standard or FEL plus 0.3;
0.05/+0.04 means an absolute level of 0.05 or an additive level of the standard or FEL plus 0.04, whilchever level is higher; these emissions
thresholds apply to the monitoring requirements of paragraph (g) of this section 86.010-18.

(1) Fuel system monitoring.
(i) General. The OBD system must monitor the fuel delivery system
to verify that it is functioning properly. The individual electronic
components (e.g., actuators, valves, sensors, pumps) that are used in
the fuel system and are not specifically addressed in this paragraph
(g)(1) must be monitored in accordance with the requirements of
paragraph (i)(3) of this section.
(ii) Fuel system malfunction criteria.
(A) Fuel system pressure control. The OBD system must monitor the
fuel system's ability to control to the desired fuel pressure. This
monitoring must be done continuously unless new hardware has to be
added, in which case the monitoring must be done at least once per
drive cycle. The OBD system must detect a malfunction of the fuel
system's pressure control system when the pressure control system is
unable to maintain an engine's emissions at or below the emissions
thresholds for ``other monitors'' as shown in Table 1 of this paragraph
(g). For engines in which no failure or deterioration of the fuel
system pressure control could result in an engine's emissions exceeding
the applicable emissions thresholds, the OBD system must detect a
malfunction when the system has reached its control limits such that
the commanded fuel system pressure cannot be delivered.
(B) Fuel system injection quantity. The OBD system must detect a
malfunction of the fuel injection system when the system is unable to
deliver the commanded quantity of fuel necessary to maintain an
engine's emissions at or below the emissions thresholds for ``other
monitors'' as shown in Table 1 of this paragraph (g). For engines in
which no failure or deterioration of the fuel injection quantity could
result in an engine's emissions exceeding the applicable emissions
thresholds, the OBD system must detect a malfunction when the system
has reached its control limits such that the commanded fuel quantity
cannot be delivered.
(C) Fuel system injection timing. The OBD system must detect a
malfunction of the fuel injection system when the system is unable to
deliver fuel at the proper crank angle/timing (e.g., injection timing
too advanced or too retarded) necessary to maintain an engine's
emissions at or below the emissions thresholds for ``other monitors''
as shown in Table 1 of this paragraph (g). For engines in which no
failure or deterioration of the fuel injection timing could result in
an engine's emissions exceeding the applicable emissions thresholds,
the OBD system must detect a malfunction when the system has reached
its control limits such that the commanded fuel injection timing cannot
be achieved.

[[Page 3296]]

(D) Fuel system feedback control. See paragraph (i)(6) of this section.
(iii) Fuel system monitoring conditions.
(A) The OBD system must monitor continuously for malfunctions
identified in paragraphs (g)(1)(ii)(A) and (g)(1)(ii)(D) of this section.
(B) The manufacturer must define the monitoring conditions for
malfunctions identified in paragraphs (g)(1)(ii)(B) and (g)(1)(ii)(C)
in accordance with paragraphs (c) and (d) of this section.
(iv) Fuel system MIL activation and DTC storage. The MIL must
activate and DTCs must be stored according to the provisions of
paragraph (b) of this section.
(2) Engine misfire monitoring.
(i) General. The OBD system must monitor the engine for misfire
causing excess emissions.
(ii) Engine misfire malfunction criteria. The OBD system must be
capable of detecting misfire occurring in one or more cylinders. To the
extent possible without adding hardware for this specific purpose, the
OBD system must also identify the specific misfiring cylinder. If more
than one cylinder is misfiring continuously, a separate DTC must be
stored indicating that multiple cylinders are misfiring. When
identifying multiple cylinder misfire, the OBD system is not required
to identify individually through separate DTCs each of the continuously
misfiring cylinders.
(iii) Engine misfire monitoring conditions.
(A) The OBD system must monitor for engine misfire during engine
idle conditions at least once per drive cycle in which the monitoring
conditions for misfire are met. The manufacturer must be able to
demonstrate via engineering analysis and/or data that the self-defined
monitoring conditions: Are technically necessary to ensure robust
detection of malfunctions (e.g., avoid false passes and false detection
of malfunctions); require no more than 1000 cumulative engine
revolutions; and, do not require any single continuous idle operation
of more than 15 seconds to make a determination that a malfunction is
present (e.g., a decision can be made with data gathered during several
idle operations of 15 seconds or less); or, satisfy the requirements of
paragraph (c) of this section with alternative engine operating conditions.
(B) Manufacturers may employ alternative monitoring conditions
(e.g., off-idle) provided the manufacturer is able to demonstrate that
the alternative monitoring ensure equivalent robust detection of
malfunctions and equivalent timeliness in detection of malfunctions.
(iv) Engine misfire MIL activation and DTC storage. The MIL must
activate and DTCs must be stored according to the provisions of
paragraph (b) of this section.
(3) EGR system monitoring.
(i) General. The OBD system must monitor the EGR system on engines
so equipped for low flow rate, high flow rate, and slow response
malfunctions. For engines equipped with EGR coolers (e.g., heat
exchangers), the OBD system must monitor the cooler for insufficient
cooling malfunctions. The individual electronic components (e.g.,
actuators, valves, sensors) that are used in the EGR system must be
monitored in accordance with the comprehensive component requirements
in paragraph (i)(3) of this section.
(ii) EGR system malfunction criteria.
(A) EGR low flow. The OBD system must detect a malfunction of the
EGR system prior to a decrease from the manufacturer's specified EGR
flow rate that would cause an engine's emissions to exceed the
emissions thresholds for ``other monitors'' as shown in Table 1 of this
paragraph (g). For engines in which no failure or deterioration of the
EGR system that causes a decrease in flow could result in an engine's
emissions exceeding the applicable emissions thresholds, the OBD system
must detect a malfunction when the system has reached its control
limits such that it cannot increase EGR flow to achieve the commanded
flow rate.
(B) EGR high flow. The OBD system must detect a malfunction of the
EGR system, including a leaking EGR valve (i.e., exhaust gas flowing
through the valve when the valve is commanded closed) prior to an
increase from the manufacturer's specified EGR flow rate that would
cause an engine's emissions to exceed the emissions thresholds for
``other monitors'' as shown in Table 1 of this paragraph (g). For
engines in which no failure or deterioration of the EGR system that
causes an increase in flow could result in an engine's emissions
exceeding the applicable emissions thresholds, the OBD system must
detect a malfunction when the system has reached its control limits
such that it cannot reduce EGR flow to achieve the commanded flow rate.
(C) EGR slow response. The OBD system must detect a malfunction of
the EGR system prior to any failure or deterioration in the capability
of the EGR system to achieve the commanded flow rate within a
manufacturer-specified time that would cause an engine's emissions to
exceed the emissions thresholds for ``other monitors'' as shown in
Table 1 of this paragraph (g). The OBD system must monitor both the
capability of the EGR system to respond to a commanded increase in flow
and the capability of the EGR system to respond to a commanded decrease
in flow.
(D) EGR system feedback control. See paragraph (i)(6) of this section.
(E) EGR cooler performance. The OBD system must detect a
malfunction of the EGR cooler prior to a reduction from the
manufacturer's specified cooling performance that would cause an
engine's emissions to exceed the emissions thresholds for ``other
monitors'' as shown in Table 1 of this paragraph (g). For engines in
which no failure or deterioration of the EGR cooler could result in an
engine's emissions exceeding the applicable emissions thresholds, the
OBD system must detect a malfunction when the system has no detectable
amount of EGR cooling.
(iii) EGR system monitoring conditions.
(A) The OBD system must monitor continuously for malfunctions
identified in paragraphs (g)(3)(ii)(A), (g)(3)(ii)(B), and
(g)(3)(ii)(D) of this section.
(B) The manufacturer must define the monitoring conditions for
malfunctions identified in paragraph (g)(3)(ii)(C) in accordance with
paragraphs (c) and (d) of this section, with the exception that
monitoring must occur every time the monitoring conditions are met
during the drive cycle rather than once per drive cycle as required in
paragraph (c)(2) of this section. For purposes of tracking and
reporting as required in paragraph (d)(1) of this section, all monitors
used to detect malfunctions identified in paragraph (g)(3)(ii)(C) of
this section must be tracked separately but reported as a single set of
values as specified in paragraph (e)(1)(iii) of this section.
(C) The manufacturer must define the monitoring conditions for
malfunctions identified in paragraph (g)(3)(ii)(E) of this section in
accordance with paragraphs (c) and (d) of this section. For purposes of
tracking and reporting as required in paragraph (d)(1) of this section,
all monitors used to detect malfunctions identified in paragraph
(g)(3)(ii)(E) of this section must be tracked separately but reported
as a single set of values as specified in paragraph (e)(1)(iii) of this
section.
(D) The manufacturer may request Administrator approval to disable
temporarily the EGR system monitor(s) under specific conditions (e.g.,
when freezing may affect performance of the system) provided the
manufacturer is

[[Page 3297]]

able to demonstrate via data or engineering analysis that a reliable
monitor cannot be run when these conditions exist.
(iv) EGR system MIL activation and DTC storage. The MIL must
activate and DTCs must be stored according to the provisions of
paragraph (b) of this section.
(4) Turbo boost control system monitoring.
(i) General. The OBD system must monitor the boost pressure control
system (e.g., turbocharger) on engines so equipped for under and over
boost malfunctions. For engines equipped with variable geometry
turbochargers (VGT), the OBD system must monitor the VGT system for
slow response malfunctions. For engines equipped with charge air cooler
systems, the OBD system must monitor the charge air cooler system for
cooling system performance malfunctions. The individual electronic
components (e.g., actuators, valves, sensors) that are used in the
boost pressure control system must be monitored in accordance with the
comprehensive component requirements in paragraph (i)(3) of this section.
(ii) Turbo boost control system malfunction criteria.
(A) Turbo underboost. The OBD system must detect a malfunction of
the boost pressure control system prior to a decrease from the
manufacturer's commanded boost pressure that would cause an engine's
emissions to exceed the emissions thresholds for ``other monitors'' as
shown in Table 1 of this paragraph (g). For engines in which no failure
or deterioration of the boost pressure control system that causes a
decrease in boost could result in an engine's emissions exceeding the
applicable emissions thresholds, the OBD system must detect a
malfunction when the system has reached its control limits such that it
cannot increase boost to achieve the commanded boost pressure.
(B) Turbo overboost. The OBD system must detect a malfunction of
the boost pressure control system prior to an increase from the
manufacturer's commanded boost pressure that would cause an engine's
emissions to exceed the emissions thresholds for ``other monitors'' as
shown in Table 1 of this paragraph (g). For engines in which no failure
or deterioration of the boost pressure control system that causes an
increase in boost could result in an engine's emissions exceeding the
applicable emissions thresholds, the OBD system must detect a
malfunction when the system has reached its control limits such that it
cannot decrease boost to achieve the commanded boost pressure.
(C) VGT slow response. The OBD system must detect a malfunction
prior to any failure or deterioration in the capability of the VGT
system to achieve the commanded turbocharger geometry within a
manufacturer-specified time that would cause an engine's emissions to
exceed the emissions thresholds for ``other monitors'' as shown in
Table 1 of this paragraph (g). For engines in which no failure or
deterioration of the VGT system response could result in an engine's
emissions exceeding the applicable emissions thresholds, the OBD system
must detect a malfunction of the VGT system when proper functional
response of the system to computer commands does not occur.
(D) Turbo boost feedback control. See paragraph (i)(6) of this section.
(E) Charge air undercooling. The OBD system must detect a
malfunction of the charge air cooling system prior to a decrease from
the manufacturer's specified cooling rate that would cause an engine's
emissions to exceed the emissions thresholds for ``other monitors'' as
shown in Table 1 of this paragraph (g). For engines in which no failure
or deterioration of the charge air cooling system that causes a
decrease in cooling performance could result in an engine's emissions
exceeding the applicable emissions thresholds, the OBD system must
detect a malfunction when the system has no detectable amount of charge
air cooling.
(iii) Turbo boost monitoring conditions.
(A) The OBD system must monitor continuously for malfunctions
identified in paragraphs (g)(4)(ii)(A), (g)(4)(ii)(B), and
(g)(4)(ii)(D) of this section.
(B) The manufacturer must define the monitoring conditions for
malfunctions identified in paragraph (g)(4)(ii)(C) of this section in
accordance with paragraphs (c) and (d) of this section, with the
exception that monitoring must occur every time the monitoring
conditions are met during the drive cycle rather than once per drive
cycle as required in paragraph (c)(2) of this section. For purposes of
tracking and reporting as required in paragraph (d)(1) of this section,
all monitors used to detect malfunctions identified in paragraph
(g)(4)(ii)(C) of this section must be tracked separately but reported
as a single set of values as specified in paragraph (e)(1)(iii) of this
section.
(C) The manufacturer must define the monitoring conditions for
malfunctions identified in paragraph (g)(4)(ii)(E) of this section in
accordance with paragraphs (c) and (d) of this section. For purposes of
tracking and reporting as required in paragraph (d)(1) of this section,
all monitors used to detect malfunctions identified in paragraph
(g)(4)(ii)(E) of this section must be tracked separately but reported
as a single set of values as specified in paragraph (e)(1)(iii) of this
section.
(iv) Turbo boost system MIL activation and DTC storage. The MIL
must activate and DTCs must be stored according to the provisions of
paragraph (b) of this section.
(5) NMHC converting catalyst monitoring.
(i) General. The OBD system must monitor the NMHC converting
catalyst(s) for proper NMHC conversion capability. For engines equipped
with catalyzed diesel particulate filter(s) (DPF) that convert NMHC
emissions, the catalyst function of the DPF must be monitored in
accordance with the DPF requirements of paragraph (g)(8) of this
section. For purposes of this paragraph (g)(5), each catalyst that
converts NMHC must be monitored either individually or in combination
with others.
(ii) NMHC converting catalyst malfunction criteria.
(A) NMHC converting catalyst conversion efficiency. The OBD system
must detect a catalyst malfunction when the catalyst conversion
capability decreases to the point that NMHC emissions exceed the
emissions thresholds for the NMHC catalyst system as shown in Table 1
of this paragraph (g). If no failure or deterioration of the catalyst
NMHC conversion capability could result in an engine's NMHC emissions
exceeding the applicable emissions thresholds, the OBD system must
detect a malfunction when the catalyst has no detectable amount of NMHC
conversion capability.
(B) NMHC converting catalyst aftertreatment assistance functions.
For catalysts used to generate an exotherm to assist DPF regeneration,
the OBD system must detect a malfunction when the catalyst is unable to
generate a sufficient exotherm to achieve DPF regeneration. For
catalysts used to generate a feedgas constituency to assist selective
catalytic reduction (SCR) systems (e.g., to increase NO₂
concentration upstream of an SCR system), the OBD system must detect a
malfunction when the catalyst is unable to generate the necessary
feedgas constituents for proper SCR system operation. For catalysts
located downstream of a DPF and used to convert NMHC emissions during
DPF regeneration, the OBD system must detect a malfunction when the
catalyst has no detectable amount of NMHC conversion capability.

[[Page 3298]]

(iii) NMHC converting catalyst monitoring conditions. The
manufacturer must define the monitoring conditions for malfunctions
identified in paragraphs (g)(5)(ii)(A) and (g)(5)(ii)(B) of this
section in accordance with paragraphs (c) and (d) of this section. For
purposes of tracking and reporting as required in paragraph (d)(1) of
this section, all monitors used to detect malfunctions identified in
paragraphs (g)(5)(ii)(A) and (g)(5)(ii)(B) of this section must be
tracked separately but reported as a single set of values as specified
in paragraph (e)(1)(iii) of this section.
(iv) NMHC converting catalyst MIL activation and DTC storage. The
MIL must activate and DTCs must be stored according to the provisions
of paragraph (b) of this section. The monitoring method for the NMHC
converting catalyst(s) must be capable of detecting all instances,
except diagnostic self-clearing, when a catalyst DTC has been erased
but the catalyst has not been replaced (e.g., catalyst over-temperature
histogram approaches are not acceptable).
(6) Selective catalytic reduction (SCR) and lean NOX catalyst monitoring.
(i) General. The OBD system must monitor the SCR and/or the lean
NO_X converting catalyst(s) for proper conversion capability.
For engines equipped with SCR systems or other catalyst systems that
use an active/intrusive reductant injection (e.g., active lean
NO_X catalysts that use diesel fuel post-injection or in-
exhaust injection), the OBD system must monitor the active/intrusive
reductant injection system for proper performance. The individual
electronic components (e.g., actuators, valves, sensors, heaters,
pumps) in the active/intrusive reductant injection system must be
monitored in accordance with the comprehensive component requirements
in paragraph (i)(3) of this section. For purposes of this paragraph
(g)(6), each catalyst that converts NO_X must be monitored
either individually or in combination with others.
(ii) SCR and lean NOX catalyst malfunction criteria.
(A) SCR and lean NOX catalyst conversion efficiency. The OBD system
must detect a catalyst malfunction when the catalyst conversion
capability decreases to the point that would cause an engine's
emissions to exceed the emissions thresholds for NO_X
aftertreatment systems as shown in Table 1 of this paragraph (g). If no
failure or deterioration of the catalyst NO_X conversion
capability could result in an engine's emissions exceeding any of the
applicable emissions thresholds, the OBD system must detect a
malfunction when the catalyst has no detectable amount of
NO_X conversion capability.
(B) SCR and lean NOX catalyst active/intrusive reductant delivery
performance. The OBD system must detect a malfunction prior to any
failure or deterioration of the system to properly regulate reductant
delivery (e.g., urea injection, separate injector fuel injection, post
injection of fuel, air assisted injection/mixing) that would cause an
engine's emissions to exceed any of the applicable emissions thresholds
for NO_X aftertreatment systems as shown in Table 1 of this
paragraph (g). If no failure or deterioration of the reductant delivery
system could result in an engine's emissions exceeding any of the
applicable thresholds, the OBD system must detect a malfunction when
the system has reached its control limits such that it is no longer
able to deliver the desired quantity of reductant.
(C) SCR and lean NOX catalyst active/intrusive reductant quantity.
If the SCR or lean NO_X catalyst system uses a reductant
other than the fuel used for the engine, or uses a reservoir/tank for
the reductant that is separate from the fuel tank used for the engine,
the OBD system must detect a malfunction when there is no longer
sufficient reductant available (e.g., the reductant tank is empty).
(D) SCR and lean NOX catalyst active/intrusive reductant quality.
If the SCR or lean NO_X catalyst system uses a reservoir/tank
for the reductant that is separate from the fuel tank used for the
engine, the OBD system must detect a malfunction when an improper
reductant is used in the reductant reservoir/tank (e.g., the reductant
tank is filled with something other than the reductant).
(E) SCR and lean NOX catalyst active/intrusive reductant feedback
control. See paragraph (i)(6) of this section.
(iii) SCR and lean NOX catalyst monitoring conditions.
(A) The manufacturers must define the monitoring conditions for
malfunctions identified in paragraphs (g)(6)(ii)(A) and (g)(6)(ii)(D)
of this section in accordance with paragraphs (c) and (d) of this
section. For purposes of tracking and reporting as required in
paragraph (d)(1) of this section, all monitors used to detect
malfunctions identified in paragraph (g)(6)(ii)(A) of this section must
be tracked separately but reported as a single set of values as
specified in paragraph (e)(1)(iii) of this section.
(B) The OBD system must monitor continuously for malfunctions
identified in paragraphs (g)(6)(ii)(B), (g)(6)(ii)(C), and
(g)(6)(ii)(E) of this section.
(iv) SCR and lean NO_X catalyst MIL activation and DTC
storage.
(A) For malfunctions identified in paragraph (g)(6)(ii)(A) of this
section, the MIL must activate and DTCs must be stored according to the
provisions of paragraph (b) of this section.
(B) For malfunctions identified in paragraphs (g)(6)(ii)(B),
(g)(6)(ii)(C), and (g)(6)(ii)(D) of this section, the manufacturer may
delay activating the MIL if the vehicle is equipped with an alternative
indicator for notifying the vehicle operator of the malfunction. The
alternative indicator must be of sufficient illumination and be located
such that it is readily visible to the vehicle operator under all
lighting conditions. If the vehicle is not equipped with such an
alternative indicator and the OBD MIL activates, the MIL may be
immediately deactivated and the corresponding DTC(s) erased once the
OBD system has verified that the reductant tank has been refilled
properly and the MIL has not been activated for any other malfunction.
The Administrator may approve other strategies that provide equivalent
assurance that a vehicle operator would be promptly notified and that
corrective action would be taken.
(C) The monitoring method for the SCR and lean NO_X
catalyst(s) must be capable of detecting all instances, except
diagnostic self-clearing, when a catalyst DTC(s) has been erased but
the catalyst has not been replaced (e.g., catalyst over-temperature
histogram approaches are not acceptable).
(7) NO_X adsorber system monitoring.
(i) General. The OBD system must monitor the NO_X
adsorber on engines so-equipped for proper performance. For engines
equipped with active/intrusive injection (e.g., in-exhaust fuel and/or
air injection) to achieve desorption of the NO_X adsorber,
the OBD system must monitor the active/intrusive injection system for
proper performance. The individual electronic components (e.g.,
injectors, valves, sensors) that are used in the active/intrusive
injection system must be monitored in accordance with the comprehensive
component requirements in paragraph (i)(3) of this section.
(ii) NO_X adsorber system malfunction criteria.
(A) NO_X adsorber system capability. The OBD system must
detect a NO_X adsorber malfunction when its capability (i.e.,
its combined adsorption and conversion capability) decreases to

[[Continued on page 3299]]

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