OBD systems to be required for HD truck engines

Dec. 4, 2008
The Environmental Protection Agency (EPA) is issuing a final rule to require onboard diagnostic (OBD) systems on heavy-duty engines used in vehicles weighing over 14,000 pounds, according to EPA information released December 4

The Environmental Protection Agency (EPA) is issuing a final rule to require onboard diagnostic (OBD) systems on heavy-duty engines used in vehicles weighing over 14,000 pounds, according to EPA information released December 4.

In addition, EPA is making changes to existing requirements for diesel highway heavy-duty vehicles under 14,000 pounds.

Advanced emissions control systems, such as catalyzed diesel particulate filters (DPF) and catalysts capable of reducing harmful nitrogen oxide (NOx) emissions, will now require monitoring for malfunctions via an OBD similar to those systems that have been required on passenger cars since the mid-1990s, EPA said.

The final rule, which becomes effective 60 days after it is published in the Federal Register,will require manufacturers to install OBD systems that monitor the functioning of emission control components and alert the vehicle operator to any detected need for emission related repair. The rule also will mandate that manufacturers make available to the service and repair industry information necessary to perform repair and maintenance service on the systems and other emission related engine components.

Some of the changes are being made for immediate implementation to relax some of the requirements currently in place for 8,500- to 14,000-pound applications that cannot be met by diesels without granting widespread deficiencies to industry. Other changes are being made for the 2010 and later model years since they represent an increase in the stringency of current OBD requirements and, therefore, some lead-time is necessary for manufacturers to comply. All of the changes being made for 8,500- to 14,000-pound diesel applications will result in OBD emissions thresholds identical, for all practical purposes, to the OBD thresholds for over 14,000 pound applications, according to the EPA information.