Test Description

The numbers below refer to the step numbers on the diagnostic table.

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. Removing the HO2S sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
2. 5
   
   This step will isolate the catalytic converter from the remainder of the exhaust system.
3. 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  3 and repeat diagnostic procedure on the opposite exhaust pipe.