Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
- Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate B52 Heated Oxygen Sensor. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 5 Ω between the low reference circuit terminal A and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, verify the appropriate scan tool B52 HO2S voltage parameter is approximately 450 mV.
- If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
- If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
- Install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S voltage parameter is less than 60 mV.
- If greater than the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the K20 Engine Control Module.
- Verify none of the following conditions exist:
- Lean fuel injectors-Refer to Fuel Injector Diagnosis (CH47976) , Fuel Injector Diagnosis (J39021 or Scan Tool)
- Water intrusion in the HO2S harness connector
- Low fuel system pressure-Refer to Fuel System Diagnosis (Without FPCM) , Fuel System Diagnosis (FPCM)
- Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis
- Exhaust leaks
- Engine vacuum leaks
- Contaminated HO2S - Silicon
- An engine mechanical condition- Symptoms - Engine Mechanical
- If you find any of the above conditions, repair as necessary.
- If all circuits test normal, replace the appropriate B52 Heated Oxygen Sensor.