Test Description
WARNING: This page is about a different car, the 2002 Pontiac Aztek and 2002 Buick Rendezvous. 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 procedures.
- 2
Check the heater current with the engine at operating temperature, and allow time for the heater current to stabilize. The HO2S 1 heater current is initially higher until the sensor reaches full operating temperature. - 4
This step ensures that the ignition voltage circuit to the HO2S 1 is not open or shorted. The test lamp should be connected to a good chassis ground, in case the HO2S 1 low reference or HO2S 1 heater low control circuit is malfunctioning. - 6
This step checks the HO2S 1 heater ground circuit. The engine must be running for the PCM to enable the heater low control driver to provide a path to ground.