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Regulatory

Announcement

 Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA420-F-98-002

January 1998

Office of Mobile Sources

Proposed Amendment to On-Board

Diagnostic Checks Requirement for

I/M Programs

The U.S. Environmental Protection Agency (EPA) is proposing to

extend, by a period of three years, the deadline by which states must

implement On-Board Diagnostic (OBD) checks as a regular part of their

I/M programs. Prior to this proposed new deadline of January 1, 2001,

states may opt to include OBD checks and fail vehicles based on OBD

failure alone. States may not earn emission reduction credit, however,

unless exhaust and evaporative tests are performed as well. Should

EPA and states complete testing and review of OBD systems sooner

than expected, the Agency may be able to make credits available to

states who choose to implement OBD I/M checks prior to the proposed

deadline.

Background

On August 6, 1996, EPA published a final rulemaking relating to the

implementation of OBD checks as a routine part of I/M programs. In the

rule, EPA interpreted the Clean Air Act requirement to include both

emission testing and OBD checks and thus required both tests as part of

the regular I/M test procedures. Ozone Transport Region (OTR) areas

with OTR low enhanced programs were to implement OBD checks by

January 1, 1999, and all other areas were to implement OBD checks by

January 1, 1998. Until January 1, 2000, OBD checks, exhaust tests and

evaporative system tests, where applicable, were to be required on each

subject vehicle of model year 1996 and newer. After January 1, 2000,

failure of the OBD test would require mandatory repair.
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Overview of Proposed Rule

This rule proposes to delay the required implementation date for OBD by

setting the new implementation deadline as January 1, 2001, for all areas

with basic and enhanced I/M programs. This amounts to a two year delay

for OTR low enhanced areas and a three year delay for all others. During

this time extension, EPA will work with states and other stakeholders to

generate, collect and analyze the data necessary to determine the effectiveness of OBD systems in an I/M setting.

EPA is currently conducting such a study which began October 1, 1997.

Two years are needed to ensure ample time for fleet penetration of OBDequipped vehicles, so that enough vehicles can be recruited for the study.

A third year will be needed to allow sufficient time to analyze the data

generated by the study.

In addition, EPA is proposing certain clarifying amendments to allow for

updates to the Code of Federal Regulations which are cross-referenced in

the OBD rule. Section 86.094-17, which includes the technical specifications for OBD systems, is periodically updated to include new requirements. This rule proposes to amend the sections of the OBD rule where

that subsection is referenced with new language which obviates the need

for future amendments in this regard.

This proposed rule does not affect the requirement that states revise their

I/M State Implementation Plans by August 6, 1998, to include the OBD

checks. Also unchanged are the sections which allow states the option to

implement OBD inspections before December 31, 1999, and to allow

failure of OBD to result in failure of the I/M test, thereby requiring

repair. However, states which choose to conduct OBD checks cannot earn

emission reduction credits for doing so unless they also perform the

exhaust and evaporative tests, where applicable, or unless EPA completes

its analysis and determines appropriate credit sooner than expected.

Effect of Proposed Rule

This proposed rule will allow the states even greater flexibility in designing and implementing I/M programs which meet their local needs and

help them to move towards attainment. In addition, it will reduce the cost

burden the states would face if they were required to run OBD checks

concurrently with the exhaust and evaporative tests as required by the

previous rule, so this amendment will produce a net savings. The I/M
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testing requirements will now be less burdensome in terms of test time,

equipment and cost. Furthermore, it is not certain that the requirement

would have generated additional emission reductions to justify the added

cost.

OBD equipment suppliers and I/M contractors may need to adjust to

shifting requirements resulting from this proposed rule. Automobile

manufacturers will see a delay in the generation of some data on OBD

in-use performance. The general public will not be affected by the

proposed delay, as it only postpones a requirement to which most have

not yet been subjected.

The proposed delay will have no appreciable effect upon the environment. The vehicles which would otherwise be subject to the OBD check

will still receive exhaust and evaporative (where applicable) testing, if

the state is earning emission reduction credits for those vehicles. Emission reductions will still be achieved for those vehicles despite the delay

in OBD checks.

For More Information

Additional documents on I/M programs and OBD are available electronically from the EPA Internet server at:

http://www.epa.gov/OMSWWW/im.htm

Document information is also available by contacting Russ Banush at:

U.S. Environmental Protection Agency

Office of Mobile Sources

2565 Plymouth Road

Ann Arbor, Michigan 48105

(734) 668-4333