EPA proposes mandatory onboard diagnostics for heavy trucks

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In a historic first, the Environmental Protection Agency has proposed requiring heavy trucks to have onboard diagnostic systems similar to those required on cars since the mid-1990s. The extensive proposal has not been published yet in the Federal Register, said Todd Sherwood, an EPA spokesman. The public will be able to comment up to 60 days after publication in the Register.

Onboard diagnostic systems in passenger vehicles monitor emissions control components, detect need for emissions-related repairs and alert the driver of problems; they also tell service technicians what problem exists. The OBD systems for highway trucks will work the same as the systems installed in cars.

The proposals are part of the Clean Diesel Truck and Bus Program, which is expected to cut emissions dramatically, thereby preventing 8,300 premature deaths, more than 9,500 hospitalizations and 1.5 million lost work days. The proposal would require:

  • For heavy-duty truck and bus engines built after 2010 and weighing more than 14,000 pounds, the EPA proposes all major emissions control systems be monitored and malfunctions be detected prior to emissions exceeding a set of thresholds. It would require monitoring of the aftertreatment device used on highway diesel engines to comply with the 2010 emissions standards, and system failures be brought to the driver’s attention. The agency also proposes all emissions-related electronic sensors and actuators be monitored for proper operation.
  • For 2010 and later highway vehicles weighing more than 14,000 pounds, officials propose one engine family per manufacturer be certified to the proposed OBD requirements in the 2010-12 model years. Beginning in 2013, highway engines for all manufacturers would have to be certified to the proposed OBD requirements.
  • For 2010 and later model year highway heavy-duty diesel vehicles weighing less than 14,000 pounds, the EPA proposes new emissions thresholds for monitoring the diesel particulate filter. This would be more stringent than the current requirement, which only detects a catastrophic failure.
  • For 2007 and later model year highway heavy-duty diesel vehicles weighing less than 14,000 pounds, officials propose a change to the existing emissions thresholds for NOx (nitrogen oxides) emissions. The existing thresholds were established when the engine’s NOx standard was much higher than today’s low level.
  • For vehicles weighing more than 14,000 pounds, the service information availability requirements would apply for those engines certified to the OBD requirements.

    More information is available at www.epa.gov.