Circuit/System Testing
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
- Verify that none of the following conditions exist:
- Inspect the appropriate HO2S 1 and HO2S 2 for being secure
- Damaged wiring between either HO2S and the ECM
- Leaking fuel injectors-Refer to Fuel Injector Solenoid Coil Test
- High fuel system pressure-Refer to Fuel System Diagnosis
- Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)
- Contaminated HO2S-Silicon
- If you find any of the above conditions, repair as necessary.
- Ignition OFF, disconnect the harness connector at the appropriate HO2S 2.
- Ignition ON, verify the scan tool HO2S 2 voltage parameter is between 400-520 mV.
- If greater than the specified range, test the HO2S 2 signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
- Connect the harness connector at the HO2S 2.
- Engine idling, raise the engine speed above 1,200 RPM for 30 seconds. Verify the scan tool HO2S 2 voltage parameter is less than 1,000 mV.
- If greater than the specified range, replace the HO2S 2.
- Engine idling, move the HO2S 1 and HO2S 2 harnesses between the HO2S harness connector and the ECM. Observe the scan tool HO2S 1 lambda parameter, and the HO2S 2 voltage parameter. Verify the parameters do not change abruptly.
- If the parameter changes abruptly, repair the harness/connections as necessary.
- If all circuits/connections test normal, replace the appropriate HO2S 1.