Restricted Exhaust

Restricted Exhaust

Diagnostic Aids

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 the perform a service regeneration. Refer to Diesel Particulate Filter (DPF) Service Regeneration (Diesel Particulate Filter (DPF) Service Regeneration).

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

Test Description

The numbers below refer to the step numbers on the diagnostic table.
4. The exhaust system has a very low back pressure under normal conditions. If the exhaust system is restricted, a significant increase in the exhaust pressure is noticed on the J 35314-A.
Removing the heated oxygen sensor (HO2S) sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
5. This step will isolate the catalytic converter from the remainder of the exhaust system.
8. Confirming that the condition has been fixed is essential. If the symptom still exists and the vehicle has a dual exhaust system, proceed to step 2 and repeat the diagnostic procedure on the opposite exhaust pipe.