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

Allowing the engine to cool before performing this test allows the HO2S 1 to cool which causes the HO2S signal voltage to return to near bias voltage, approximately 450 millivolts. After the HO2S 1 heater is commanded ON, the HO2S will heat up. This will cause the signal voltage to change either more than or less than bias voltage, verifying the HO2S 1 heater is operating.

4

Tests for voltage at the HO2S 1 heater. The Oxygen Sensor (O2) fuse supplies power to the HO2S 1 heater.

5

This test verifies that the PCM is providing ground to the HO2S 1 heater.

6

This step tests if ground is constantly being applied to the HO2S 1 heater.