EPA to Require OBD Systems Starting in 2010

This story appears in the March 9 print edition of Transport Topics.

The Environmental Protection Agency will require onboard diagnostics systems on at least one engine family per manufacturer starting in 2010.

EPA’s final OBD rule formally takes effect on April 27. If a truck’s emissions of nitrogen oxides and particulate matter rise to twice the allowable levels mandated by EPA’s 2010 standard — 0.2 grams per brake horsepower-hour for nitrogen oxides and 0.01 g/bhp-hr for particulate matter — the driver must be alerted by a warning light.

By 2019, all engines will have to comply with the mandate, and the OBD systems will have to alert drivers whenever emissions exceed the 2010 threshold, EPA said in its Federal Register notice.

“OBD is a complex and difficult regulation with which to comply,” EPA said. “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.”

OBD systems use electronic sensors to communicate with engine control modules and ensure that emission control technology is functioning properly.

The release of EPA’s final rule follows by about six months the publication of a similar mandate by the California Air Resources Board, which obtained a waiver from EPA in September to create its own on-board diagnostics regulations for heavy-duty diesel engines.

The EPA rule does not differ significantly from the OBD standards set by California, a representative of the Engine Manufacturers Association told Transport Topics.

“Overall, the rules are very close,” said Joe Suchecki, an EMA spokesman. However, “there are a couple differences between the EPA and California rules, but EMA is hoping that will we continue to work with both agencies and get those to be harmonized so we can do one OBD system for the whole country.”

In the meantime, there is enough harmony between the two regulations that OBD systems certified to EPA’s rule still will be able to operate in California next year, Suchecki said.

“The major point of difference [is] the OBD requirements for nitrogen oxides and particulate matter in 2016 — it seems like EPA’s are a little less stringent than those being proposed by California,” said Glen Kedzie, vice president of environmental affairs and assistant general counsel for American Trucking Associations.

One stumbling block preventing a quick tightening of alert threshold for heavy-duty OBD systems is the lack of sophisticated sensors, Suchecki said.

“The technology is just not there to get very accurate measurements on the sensors,” he said. “That’s something that will be developed.”

Of particular concern to manufacturers is the lack of sensor technology for measuring levels of particulate matter, Suchecki said.

EPA acknowledged the dearth of particulate matter sensor technology in a technical support document released along with the final rule, noting that “sensors which can directly measure exhaust PM will not be available for commercial sale in 2010.”

Nevertheless, CARB has publicly urged EPA to push ahead with stricter alert thresholds.

In comments submitted to EPA in December, CARB urged the agency “to adopt the more stringent thresholds now to provide a clear goal for industry to design for.”

EPA countered that “certain sensor capabilities have not advanced as we expected” and that tightening emission thresholds too quickly could “lead to more OBD detections and more OBD-induced repairs and, perhaps, many OBD-induced repairs for malfunctions having little impact on emissions.”