Restricted Exhaust
Restricted ExhaustTools Required
^ J 35314-A Exhaust Back Pressure Gage
Diagnostic Aids
Caution: While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system.
For dual exhaust systems a quick check of exhaust flow will help determine which side of the exhaust system is restricted. The side that has less exhaust flow is the side that will be suspect, and diagnosis should begin there.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
4. The exhaust system has 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 AIR check valve or HO2S sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
5. If high back pressure is not found at idle, increasing the engine speed may help find a restriction.
Perform operational check before returning vehicle to customer.
6. This step will isolate the catalytic converter from the remainder of the exhaust system.
9. 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 diagnostic procedure on the opposite exhaust pipe.
Restricted Exhaust
Test 1 - 3:
Test 4 - 7:
Test 8 - 9:
