Test Description
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers in the diagnostic procedure.
- 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 procedure, ensure to clear all codes.
- 5 - This step will isolate the catalytic converter from the remainder of the exhaust system.