Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the HO2S 2.
- Ignition ON, load test for B+ between the ignition voltage circuit terminal E and ground.
- If less than the specified range, repair the ignition voltage circuit for a short to ground, or an open/high resistance.
- Connect a 3A fused jumper wire between the high signal circuit terminal B and ground. Verify the scan tool HO2S 2 voltage parameter is less than 10 mV.
- If greater than the specified range, repair the high signal circuit for an open/high resistance.
- Connect a 3A fused jumper wire between the high signal circuit terminal B and the low signal circuit terminal A. Verify the scan tool HO2S 2 voltage parameter is less than 10 mV.
- If greater than the specified range, test the low signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Test for less than 5 ohms of resistance between the heater control circuit terminal D and the ECM.
- If greater than the specified range, repair the heater control circuit for an open/high resistance.
- If all conditions test normal, replace the HO2S 2.