Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

1. 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 Exhaust Back Pressure Gauge (J 35314-A). Removing the AIR check valve or HO2S may set a DTC. When diagnosis is finished, ensure to clear all codes using the scan tool.
2. 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.
3. 6
   
   This step will isolate the catalytic converter from the remainder of the exhaust system.
4. 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.