Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the HO2S 2.
- Ignition ON, observe the scan tool HO2S 2 voltage parameter. The parameter should display between 350-550 mV.
- If greater than the specified range, test the high signal circuit for a short to the heater control circuit. If the circuit tests normal, replace the ECM.
- If all circuits test normal, replace the HO2S 2.