Test Description
WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The number below refer to the step number on the diagnostic procedure.
- 2
As the heater warms the HO2S to operating temperature, the HO2S will output a voltage in relation to the amount of oxygen in the exhaust. With the ignition ON and the engine OFF, the exhaust usually contains a high oxygen content. With the engine OFF the HO2S voltage will usually decrease from the initial, or bias, voltage due to the high oxygen content. - 4
This step checks for proper HO2S 2 heater ignition 1 voltage and ground supply. - 5
This step checks for proper PCM and signal circuit operation.