Circuit/System Testing
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
- Engine operating, move the related HO2S 2 harnesses for the appropriate sensor between the HO2S 2 harness connector and the ECM while monitoring the appropriate scan tool HO2S voltage parameter. Verify that the HO2S parameter does not change abruptly while moving the related harnesses.
- If the HO2S parameter does change abruptly while moving the related harnesses, repair the circuit as necessary.
- Ignition OFF, disconnect the harness connector of the appropriate HO2S 2.
- Ignition ON, verify the scan tool HO2S 2 voltage parameter is between 400-520 mV.
- If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit/connections test normal, replace the ECM.
- Verify that none of the following conditions exist:
- Lean fuel injectors-Refer to Fuel Injector Solenoid Coil Test .
- Water intrusion in the HO2S harness connector
- Low fuel system pressure-Refer to Fuel System Diagnosis .
- Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (w/o Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (w/ Special Tool) .
- The vacuum hoses for splits, kinks, and proper connection
- The air intake system after the MAF sensor for vacuum leaks
- Exhaust system leaks
- Contaminated HO2S - Silicon
- An engine mechanical condition-Refer to Symptoms - Engine Mechanical .
- If you find any of the above conditions, repair as necessary.
- If all circuits/connections test normal, replace the appropriate HO2S 2.