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Heavy Trucks, Buses, and Engines

Heavy-Duty Engine Recalls

Navistar Inc. recently began recalling approximately 4,400 trucks equipped with 11 liter engines to install a new software calibration they developed to ensure these vehicle’s engines comply with the emission levels they were designed to meet. (see report)

This page presents general information about recalls of heavy-duty (HD) highway engines such as those in trucks and buses.


Engine manufacturers are required to design and build their engines to meet emission standards for the useful life of the engines as specified by law. Under Section 207 of the Clean Air Act, if EPA determines that a substantial number of engines in a class or category do not meet emission standards in actual use even though they are properly maintained and used, EPA can require the manufacturer to recall and fix the affected engines.

EPA conducts "real world" on the road testing of vehicles and engines using portable emissions measurment systems (PEMS). If problems are found during the course of EPA testing, discussions begin with the manufacturer on possible remedies, which may include a recall of the affected engines. Manufacturers currently participate in a pilot in-use testing program. In the future manufacturers will be required to conduct their own in-use testing and provide the test results to EPA.

Manufacturers are required to report certain defects they find to EPA if they affect emission-related parts. Many times the discovery of these defects leads to voluntary recalls or service campaigns. Manufacturers are also required to report to EPA all emission-related voluntary recalls.

Recalls and other remedies are usually conducted voluntarily by the manufacturer, although EPA has the authority to order a manufacturer to recall and fix noncomplying engines. Most recalls are initiated voluntarily by manufacturers once a potential noncompliance is discovered. These voluntary actions could be influenced indirectly by the potential for EPA action. Some voluntary recalls are directly influenced via EPA in discussions with manufacturers.

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Reports of Engine Recalls

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