Test Description

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 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 procedures.

2

The HO2S should be allowed to cool before you perform this test. If the HO2S heater is functioning, the signal voltage will gradually increase or decrease as the sensor element warms. If the heater is not functioning, the HO2S signal will remain near the 450 mv bias voltage.

4

This step ensures that the ignition 1 voltage circuit to the HO2S is not open or shorted. The test lamp should be connected to a good chassis ground, in the event the HO2S low signal or HO2S heater ground circuit is malfunctioning.

5

This step tests the HO2S heater ground circuit.

6

This step tests for an open or shorted HO2S heater element.

11

Open HO2S high or low signal circuits can cause the DTC to set with a good HO2S. Test the HO2S high signal and test the HO2S low signal circuits before replacing the sensor.