Diagnostic Aids

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system.

NOTE: Do not replace a restricted particulate filter. Repair the engine condition that clogged the particulate filter, and then attempt to perform a service regeneration. Refer to Diesel Particulate Filter (DPF) Service Regeneration .

If the vehicle is equipped with a 6.6 L diesel engine do not perform this diagnostic. The exhaust system does not have a location for installing the J 35314-A Exhaust Back Pressure Gage. See Special Tools . Instead remove the suspect component, operate the vehicle, verify for improved performance. If performance is improved then replace the faulty component.