Test Description
WARNING: This page is about a different car, the 2002 GMC Savana and 2002 Chevrolet Chevy Express. 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
After the ignition is turned ON, the HO2S heater heats up causing the HO2S signal voltage to either increase or decrease. This indicates that the HO2S heater is okay. - 3
If the HO2S voltage is varying outside the specified range, the condition is not present. - 5
If the voltage is below the specified value, the high signal circuit, the low signal circuit, and the PCM are okay. - 6
If the voltage is above the specified value, the low signal circuit is okay. - 12
All oxygen sensors must be disconnected to isolate a short to ground in the HO2S heater ignition 1 voltage circuit. - 14
Resistance within the specified range indicates the HO2S heater is okay.