Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

1. 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.
2. 3
   
   If the HO2S voltage is varying outside the specified range, the condition is not present.
3. 6
   
   If the voltage is below the specified value, the high signal circuit, the low reference circuit, and the PCM are okay.
4. 15
   
   Resistance within the specified range indicates the HO2S heater is okay.