[Code of Federal Regulations]
[Title 40, Volume 17]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR86.094-25]

[Page 280-285]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 86_CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND 
ENGINES--Table of Contents
 
Subpart A_General Provisions for Emission Regulations for 1977 and Later 
 
Sec. 86.094-25  Maintenance.

    (a)(1) Applicability. This section applies to light-duty vehicles, 
light-duty trucks, and heavy-duty engines.
    (2) Maintenance performed on vehicles, engines, subsystems, or 
components used to determine exhaust or evaporative emission 
deterioration factors is classified as either emission-related or non-
emission-related and each of these can be classified as either scheduled 
or unscheduled. Further, some emission-related maintenance is also 
classified as critical emission-related maintenance.
    (b) This section specifies emission-related scheduled maintenance 
for purposes of obtaining durability data and for inclusion in 
maintenance instructions furnished to purchasers of new motor vehicles 
and new motor vehicles engines under Sec. 86.087-38.
    (1) All emission-related scheduled maintenance for purposes of 
obtaining durability data must occur at the same mileage intervals (or 
equivalent intervals if engines, subsystems, or components are used) 
that will be specified in the manufacturer's maintenance instructions 
furnished to the ultimate purchaser of the motor vehicle or engine under 
Sec. 86.094-35. This maintenance schedule may be updated as necessary 
throughout the testing of the vehicle/engine, provided that no 
maintenance operation is deleted from the maintenance schedule after the 
operation has been performed on the test vehicle or engine.
    (2) Any emission-related maintenance which is performed on vehicles, 
engines, subsystems, or components must be technologically necessary to 
assure in-use compliance with the emission standards. The manufacturer 
must submit data which demonstrate to the Administrator that all of the 
emission-related scheduled maintenance which is to be performed is 
technologically necessary. Scheduled maintenance must be approved by the 
Administrator prior to being performed or being included in the 
maintenance instructions provided to purchasers under Sec. 86.087-38. 
The Administrator has determined that emission-related maintenance at 
shorter intervals than those outlined in paragraphs (b) (3) and (4) of 
this section is not technologically necessary to ensure in-use 
compliance. However, the Administrator may determine that maintenance 
even more restrictive (e.g., longer intervals) than that listed in 
paragraphs (b) (3) and (4) of this section is also not technologically 
necessary.
    (3) For Otto-cycle light-duty vehicles, light-duty trucks and heavy 
duty engines, emission-related maintenance in addition to, or at shorter 
intervals than, that listed in paragraphs (b)(3) (i) through (vii) of 
this section will not be accepted as technologically necessary,

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except as provided in paragraph (b)(7) of this section.
    (i)(A) The cleaning or replacement of light-duty vehicle or light-
duty truck spark plugs shall occur at 30,000 miles of use and at 30,000-
mile intervals thereafter.
    (B) The cleaning or replacement of Otto-cycle heavy duty engine 
spark plugs shall occur at 25,000 miles (or 750 hours) of use and at 
25,000-mile (or 750-hour) intervals thereafter, for engines certified 
for use with unleaded fuel only.
    (ii) For light-duty vehicles and light-duty trucks, the adjustment, 
cleaning, repair, or replacement of the items listed in paragraphs 
(b)(3)(ii) (A) through (D) of this section shall occur at 50,000 miles 
of use and at 50,000-mile intervals thereafter.
    (A) Positive crankcase ventilation valve.
    (B) Emission-related hoses and tubes.
    (C) Ignition wires.
    (D) Idle mixture.
    (iii) For heavy-duty engines, the adjustment, cleaning, repair, or 
replacement of the items listed in paragraphs (b)(3)(iii) (A) through 
(D) of this section shall occur at 50,000 miles (or 1,500 hours) of use 
and at 50,000-mile (or 1,500-hour) intervals thereafter.
    (A) Positive crankcase ventilation valve.
    (B) Emission-related hoses and tubes.
    (C) Ignition wires.
    (D) Idle mixture.
    (iv) For light-duty vehicles, light-duty trucks and heavy-duty 
engines, the adjustment, cleaning, repair, or replacement of the oxygen 
sensor shall occur at 80,000 miles (or 2,400 hours) of use and at 
80,000-mile (or 2,400-hour) intervals thereafter.
    (v) For heavy-duty engines, the adjustment, cleaning, repair, or 
replacement of the items listed in paragraphs (b)(3)(v) (A) through (G) 
of this section shall occur at 100,000 miles (or 3,000 hours) of use and 
at 100,000-mile (or 3,000-hour) intervals thereafter.
    (A) Catalytic converter.
    (B) Air injection system components.
    (C) Fuel injectors.
    (D) Electronic engine control unit and its associated sensors 
(except oxygen sensor) and actuators.
    (E) Evaporative emission canister.
    (F) Turbochargers.
    (G) Carburetors.
    (vi) For light-duty vehicles and light-duty trucks, the adjustment, 
cleaning, repair, or replacement of the items listed in paragraphs 
(b)(3)(vi) (A) through (I) of this section shall occur at 100,000 miles 
of use and at 100,000-mile intervals thereafter.
    (A) Catalytic converter.
    (B) Air injection system components.
    (C) Fuel injectors.
    (D) Electronic engine control unit and its associated sensors 
(except oxygen sensor) and actuators.
    (E) Evaporative emission canister.
    (F) Turbochargers.
    (G) Carburetors.
    (H) Superchargers.
    (I) EGR System including all related filters and control valves.
    (vii) For heavy-duty engines certified for use with unleaded fuel 
only, the adjustment, cleaning, repair, or replacement of the EGR system 
(including all related filters and control valves) shall occur at 50,000 
miles (or 1,500 hours) of use and at 50,000-mile (or 1,500-hour) 
intervals thereafter.
    (4) For diesel-cycle light-duty vehicles, light-duty trucks, and 
heavy-duty engines, emission-related maintenance in addition to, or at 
shorter intervals than that listed in paragraphs (b)(4) (i) through (iv) 
of this section will not be accepted as technologically necessary, 
except as provided in paragraph (b)(7) of this section.
    (i) For heavy-duty engines, the adjustment, cleaning, repair, or 
replacement of the items listed in paragraphs (b)(4)(i) (A) through (C) 
of this section shall occur at 50,000 miles (or 1,500 hours) of use and 
at 50,000-mile (or 1,500-hour) intervals thereafter.
    (A) Exhaust gas recirculation system including all related filters 
and control valves.
    (B) Positive crankcase ventilation valve.
    (C) Fuel injector tips (cleaning only).
    (ii) For light-duty vehicles and light-duty trucks, the adjustment, 
cleaning, repair, or replacement of the positive crankcase ventilation 
valve shall occur at 50,000 miles of use and at 50,000-mile intervals 
thereafter.
    (iii) The adjustment, cleaning, repair, or replacement of items 
listed in

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paragraphs (b)(4)(iii) (A) through (D) of this section shall occur at 
100,000 miles (or 3,000 hours) of use and at 100,000-mile (or 3,000-
hour) intervals thereafter for light heavy-duty engines, or, at 150,000 
miles (or 4,500 hours) intervals thereafter for medium and heavy-duty 
engines.
    (A) Fuel injectors.
    (B) Turbocharger.
    (C) Electronic engine control unit and its associated sensors and 
actuators.
    (D) Particulate trap or trap-oxidizer system (including related 
components).
    (iv) For light-duty vehicles and light-duty trucks, the adjustment, 
cleaning, repair, or replacement shall occur at 100,000 miles of use and 
at 100,000-mile intervals thereafter of the items listed in paragraphs 
(b)(4)(iv) (A) through (G) of this section.
    (A) Fuel injectors.
    (B) Turbocharger.
    (C) Electronic engine control unit and its associated sensors and 
actuators.
    (D) Particulate trap or trap-oxidizer system (including related 
components).
    (E) Exhaust gas recirculation system including all related filters 
and control valves.
    (F) Catalytic converter.
    (G) Superchargers.
    (5) [Reserved]
    (6)(i) The components listed in paragraphs (b)(6)(i) (A) through (G) 
of this section are currently defined as critical emission-related 
components.
    (A) Catalytic converter.
    (B) Air injection system components.
    (C) Electronic engine control unit and its associated sensors 
(including oxygen sensor if installed) and actuators.
    (D) Exhaust gas recirculation system (including all related filters 
and control valves).
    (E) Positive crankcase ventilation valve.
    (F) Evaporative emission control system components (excluding 
canister air filter).
    (G) Particulate trap or trap-oxidizer system.
    (ii) All critical emission-related scheduled maintenance must have a 
reasonable likelihood of being performed in-use. The manufacturer shall 
be required to show the reasonable likelihood of such maintenance being 
performed in-use, and such showing shall be made prior to the 
performance of the maintenance on the durability data vehicle. Critical 
emission-related scheduled maintenance items which satisfy one of the 
conditions defined in paragraphs (b)(6)(ii) (A) through (F) of this 
section will be accepted as having a reasonable likelihood of the 
maintenance item being performed in-use.
    (A) Data are presented which establish for the Administrator a 
connection between emissions and vehicle performance such that as 
emissions increase due to lack of maintenance, vehicle performance will 
simultaneously deteriorate to a point unacceptable for typical driving.
    (B) Survey data are submitted which adequately demonstrate to the 
Administrator that, at an 80 percent confidence level, 80 percent of 
such engines already have this critical maintenance item performed in-
use at the recommended interval(s)
    (C) A clearly displayed visible signal system approved by the 
Administrator is installed to alert the vehicle driver that maintenance 
is due. A signal bearing the message ``maintenance needed'' or ``check 
engine,'', or a similar message approved by the Administrator, shall be 
actuated at the appropriate mileage point or by component failure. This 
signal must be continuous while the engine is in operation and not be 
easily eliminated without performance of the required maintenance. 
Resetting the signal shall be a required step in the maintenance 
operation. The method for resetting the signal system shall be approved 
by the Administrator.
    (D) A manufacturer may desire to demonstrate through a survey that a 
critical maintenance item is likely to be performed without a visible 
signal on a maintenance item for which there is no prior in-use 
experience without the signal. To that end, the manufacturer may in a 
given model year market up to 200 randomly selected vehicles per 
critical emission-related maintenance item without such visible signals, 
and monitor the performance of the critical maintenance item by the 
owners to show compliance with paragraph (b)(6)(ii)(B) of this section. 
This

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option is restricted to two consecutive model years and may not be 
repeated until any previous survey has been completed. If the critical 
maintenance involves more than one engine family, the sample will be 
sales weighted to ensure that it is representative of all the families 
in question.
    (E) The manufacturer provides the maintenance free of charge, and 
clearly informs the customer that the maintenance is free in the 
instructions provided under Sec. 86.087-38.
    (F) Any other method which the Administrator approves as 
establishing a reasonable likelihood that the critical maintenance will 
be performed in-use.
    (iii) Visible signal systems used under paragraph (b)(6)(ii)(C) of 
this section are considered an element of design of the emission control 
system. Therefore, disabling, resetting, or otherwise rendering such 
signals inoperative without also performing the indicated maintenance 
procedure is a prohibited act under section 203(a)(3) of the Clean Air 
Act (42 U.S.C. 7522(a) (3)).
    (7) Changes to scheduled maintenance. (i) For maintenance practices 
that existed prior to the 1980 model year, only the maintenance items 
listed in paragraphs (b) (3) and (4) of this section are currently 
considered by EPA to be emission-related. The Administrator may, 
however, determine additional scheduled maintenance items that existed 
prior to the 1980 model year to be emission-related by announcement in a 
Federal Register Notice. In no event may this notification occur later 
than September 1 of the calendar year two years prior to the affected 
model year.
    (ii) In the case of any new scheduled maintenance, the manufacturer 
must submit a request for approval to the Administrator for any 
maintenance that it wishes to recommend to purchasers and perform during 
durability determination. New scheduled maintenance is that maintenance 
which did not exist prior to the 1980 model year, including that which 
is a direct result of the implementation of new technology not found in 
production prior to the 1980 model year. The manufacturer must also 
include its recommendations as to the category (i.e., emission-related 
or non-emission-related, critical or non-critical) of the subject 
maintenance and, for suggested emission-related maintenance, the maximum 
feasible maintenance interval. Such requests must include detailed 
evidence supporting the need for the maintenance requested, and 
supporting data or other substantiation for the recommended maintenance 
category and for the interval suggested for emission-related 
maintenance. Requests for new scheduled maintenance must be approved 
prior to the introduction of the new maintenance. The Administrator will 
then designate the maintenance as emission-related or non-emission-
related. For maintenance items established as emission-related, the 
Administrator will further designate the maintenance as critical if the 
component which receives the maintenance is a critical component under 
paragraph (b)(6) of this section. For each maintenance item designated 
as emission-related, the Administrator will also establish a 
technologically necessary maintenance interval, based on industry data 
and any other information available to EPA. Designations of emission-
related maintenance items, along with their identification as critical 
or non-critical, and establishment of technologically necessary 
maintenance intervals, will be announced in the Federal Register.
    (iii) Any manufacturer may request a hearing on the Administrator's 
determinations in paragraph (b)(7) of this section. The request shall be 
in writing and shall include a statement specifying the manufacturer's 
objections to the Administrator's determinations, and data in support of 
such objections. If, after review of the request and supporting data, 
the Administrator finds that the request raises a substantial factual 
issue, he shall provide the manufacturer a hearing in accordance with 
Sec. 86.078-6 with respect to such issue.
    (c) Non-emission-related scheduled maintenance which is reasonable 
and technologically necessary (e.g., oil change, oil filter change, fuel 
filter change, air filter change, cooling system maintenance, adjustment 
of idle speed, governor, engine bolt torque, valve lash, injector lash, 
timing, adjustment of air pump drive belt tension, lubrication of the 
exhaust manifold heat control valve, lubrication of

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carburetor choke linkage, retorqueing carburetor mounting bolts, etc.) 
may be performed on durability data vehicles at the least frequent 
intervals recommended by the manufacturer to the ultimate purchaser, 
(e.g., not at the intervals recommended for severe service).
    (d) Unscheduled maintenance on light-duty durability data vehicles. 
(1) Unscheduled maintenance may be performed during the testing used to 
determine deterioration factors, except as provided in paragraphs (d) 
(2) and (3) of this section, only under the following provisions defined 
in paragraphs (d)(1) (i) through (iii) of this section.
    (i) A fuel injector or spark plug may be changed if a persistent 
misfire is detected.
    (ii) Readjustment of an Otto-cycle vehicle cold-start enrichment 
system may be performed if there is a problem of stalling.
    (iii) Readjustment of the engine idle speed (curb idle and fast 
idle) may be performed in addition to that performed as scheduled 
maintenance under paragraph (c) of this section if the idle speed 
exceeds the manufacturer's recommended idle speed by 300 rpm or more, or 
if there is a problem of stalling.
    (2) Any other unscheduled vehicle, emission control system, or fuel 
system adjustment, repair, removal, disassembly, cleaning, or 
replacement during testing to determine deterioration factors shall be 
performed only with the advance approval of the Administrator. Such 
approval will be given if the Administrator:
    (i) Has made a preliminary determination that the part failure or 
system malfunction, or the repair of such failure or malfunction, does 
not render the vehicle or engine unrepresentative of vehicles or engines 
in-use and does not require direct access to the combustion chamber, 
except for spark plug, fuel injection component, or removable prechamber 
removal or replacement.
    (ii) Has made a determination that the need for maintenance or 
repairs is indicated by an overt indication of malfunction such as 
persistent misfiring, engine stalling, overheating, fluid leakage, loss 
of oil pressure, excessive fuel consumption, or excessive power loss. 
The Administrator shall be given the opportunity to verify the existence 
of an overt indication of part failure and/or vehicle/engine malfunction 
(e.g., misfiring, stalling, black smoke), or an activation of an audible 
and/or visible signal, prior to the performance of any maintenance to 
which such overt indication or signal is relevant under the provisions 
of this section.
    (iii) Has made a determination that the OBD system of a durability 
data vehicle representing an engine family certifying fully to the 
Federal OBD requirements as specified in Sec. 86.094-17(a) through (h) 
has specifically detected the problem and has illuminated the 
malfunction indicator light.
    (3) Emission measurement may not be used as a means of determining 
the need for unscheduled maintenance under paragraph (d)(2) of this 
section, except under the conditions defined in paragraphs (d)(3) (i) 
through (ii) of this section.
    (i) The Administrator may approve unscheduled maintenance on 
durability data vehicles based upon a significant change in emission 
levels that indicates a vehicle or engine malfunction. In these cases 
the Administrator may first approve specific diagnostic procedures to 
identify the source of the problem. The Administrator may further 
approve of specific corrections to the problem after the problem has 
been identified. The Administrator may only approve the corrective 
action after it is determined that:
    (A) The malfunction was caused by nonproduction build practices or 
by a previously undetected design problem;
    (B) The malfunction will not occur in production vehicles or engines 
in-use; and
    (C) The deterioration factor generated by the durability data 
vehicle or engine will remain unaffected by the malfunction or by the 
corrective action (e.g., the malfunction was present for only a short 
period of time before detection, replacement parts are functionally 
representative of the proper mileage or hours, etc.).
    (ii) Following any unscheduled maintenance approved under paragraph

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(d)(3)(i) of this section, the manufacturer shall perform an after-
maintenance emission test. If the Administrator determines that the 
after-maintenance emission levels for any pollutant indicates that the 
deterioration factor is no longer representative of production, the 
Administrator may disqualify the durability data vehicle or engine.
    (4) If the Administrator determines that part failure or system 
malfunction occurrence and/or repair rendered the vehicle/engine 
unrepresentative of vehicles in-use, the vehicle/engine shall not be 
used for determining deterioration factors.
    (5) Repairs to vehicle components of a durability data vehicle other 
than the engine, emission control system, or fuel system, shall be 
performed only as a result of part failure, vehicle system malfunction, 
or with the advance approval of the Administrator.
    (e) Maintenance on emission data vehicles and engines. (1) 
Adjustment of engine idle speed on emission data vehicles may be 
performed once before the low-mileage/low-hour emission test point. Any 
other engine, emission control system, or fuel system adjustment, 
repair, removal, disassembly, cleaning, or replacement on emission data 
vehicles shall be performed only with the advance approval of the 
Administrator.
    (2)-(3) [Reserved]
    (4) Repairs to vehicle components of an emission data vehicle other 
than the engine, emission control system, or fuel system, shall be 
performed only as a result of part failure, vehicle system malfunction, 
or with the advance approval of the Administrator.
    (f) Equipment, instruments, or tools may not be used to identify 
malfunctioning, maladjusted, or defective engine components unless the 
same or equivalent equipment, instruments, or tools will be available to 
dealerships and other service outlets and:
    (1) Are used in conjunction with scheduled maintenance on such 
components; or
    (2) Are used subsequent to the identification of a vehicle or engine 
malfunction, as provided in paragraph (d)(2) of this section for 
durability data vehicles or in paragraph (e)(1) of this section for 
emission data vehicles; or
    (3) Unless specifically authorized by the Administrator.
    (g)(1) Paragraph (g) of this section applies to light-duty vehicles.
    (2) Complete emission tests (see Sec. Sec. 86.106 through 86.145) 
are required, unless waived by the Administrator, before and after 
scheduled maintenance approved for durability data vehicles. The 
manufacturer may perform emission tests before unscheduled maintenance. 
Complete emission tests are required after unscheduled maintenance which 
may reasonably be expected to affect emissions. The Administrator may 
waive the requirement to test after unscheduled maintenance. These test 
data may be submitted weekly to the Administrator, but shall be air 
posted or delivered within 7 days after completion of the tests, along 
with a complete record of all pertinent maintenance, including a 
preliminary engineering report of any malfunction diagnosis and the 
corrective action taken. A complete engineering report shall be 
delivered to the Administrator concurrently with the manufacturer's 
application for certification.
    (h) All test data, maintenance reports, and required engineering 
reports shall be compiled and provided to the Administrator in 
accordance with Sec. 86.090-23.

[58 FR 4018, Jan. 12, 1993, as amended at 58 FR 9487, Feb. 19, 1993]