United States
Environmental Protection
Agency
Air and Radiation
EPA420-F-01-002
January 2001
Office of Transportation and Air Quality
SEPA Regulatory
Announcement
Final Amendments to Inspection and
Maintenance Programs
The U. S. Environmental Protection Agency (EPA) is issuing a final
rulemaking to incorporate the use of Onboard Diagnostic (OBD)
technology into motor vehicle inspection and maintenance (l/M)
programs. EPA is amending the current l/M rule and OBD testing
requirements to provide states with g~eater flexibility so they can
maximize the cost effectiveness and efficiency of their l/M program s,
while still achieving the air quality goals of the program.
Background
Under the 1990 CleanAir Act Amendments, states required to imple-
ment vehicle I/M programs are also required to incorporate a check of
the OBD computer as part of those I/M programs. On November 5,
1992, EPA published the I/M rule but did not address OBD requirements
because certification regulations for OBD had not been finalized. The
1992 rule has been amended twice to address OBD requirements in 1996
and again in 1998. Since these amendments, EPA has learned much
about the effective implementation of OBD in I/M programs as a result
of pilot testing conducted by EPA and the states. The amendments in this
final rule reflect EPA's findings as well as comments received in re-
sponse to the September 20, 2000, proposed rule. The amendments
streamline requirements and remove regulatory obstacles to help achieve
effective implementation of the OBD-I/M testing required of all I/M
programs under the 1990 CleanAir Act.
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Final Rule Overview
EPA is amending the I/M rule and ORD testing requirements to provide
states with the greater flexibility they need to better meet local needs and
to update requirements based on technological changes. These amend-
ments will also help states optimize program efficiency and the cost
effectiveness of their I/M programs by allowing them to eliminate func-
tionally redundant testing requirements. The amendments will allow
OBD system checks to replace traditional I 'M tests on model year 1996
and newer vehicles.
EPA based these amendments on: the results of four OBD-I/M pilot
studies. ERA's discussions with states regarding their preparedness for
OBD-I/M testing, recommendations made by the OBD Workgroup of the
Mobile Source Technical Review Committee of the Clean Air Scientific
Advisor^' Committee, and comments received in response to the Septem-
ber 20, 2000. proposed rule.
The amendments will also allow three options for delaying and/or phas-
ing in the mandatory start date for conducting OBD system checks.
These options will provide states the time necessary to better educate the
public and the testing and repair industries about OBD emission control
technology, and to help achieve effective implementation of I/M pro-
grams.
Key Elements of the Final Rule
•	Extends the current deadline for mandatory implementation of the
OBD-I/M inspection from January 1, 2001, to January 1, 2002.
•	Allows states showing good cause up to an additional 12 months
beyond January 1. 2002, before mandator}' OBD failure and imme-
diate repair occurs.
•	Allows I 'M programs a onc-test-cyclc phase-in period for the OBD
check during which OBD-failing vehicles will only require repair if
the vehicle also fails a tailpipe emission test.
•	Clarifies that I/M programs may use periodic checks of the OBD
system on model year 1996 and newer OBD-equipped vehicles in
lieu of (as opposed to in addition to) existing exhaust and evapora-
tive system purge and fill-neck pressure tests on those same ve-
hicles.
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•	Establishes the modeling methodology to be used by states in their
State Implementation Plans (SIPs) to account for the replacement of
traditional I M tests by ORD-I/M testing and repair, prior to manda-
tory use of MORILE6 and subsequent iterations of EPA's mobile
source emission factor model,
•	Simplifies the OBD-l/M failure criteria to include any trouble code
that causes the "Check Engine" light to go on.
For More Information
You can access documents on OBD in I'M programs electronically on
the Office of Transportation and Air Quality Web site at:
www.epa.gov otaq 'rcgs im obd obd-im.litm
Eor more information on this final rulemaking, please contact Dave
Sosnowski at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
2000 Traverwood Drive
Ann Arbor. MI 48105
734-214-4823
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