Circuit/System Testing

WARNING: This page is about a different car, the 2008 Suzuki Swift +, 2008 Pontiac Wave, and 2008 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the harness connector at the appropriate HO2S.
Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit and ground.
- HO2S 2 (Euro IV) low reference circuit terminal 3
- HO2S 2 (Non Euro IV) low reference circuit terminal 1
- If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
Engine running, verify the scan tool HO2S parameter is between 350-500 mV.
- If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Verify none of the following conditions exist:
- Rich fuel injectors-Refer to Fuel Injector Balance Test with Special Tool .
- Water intrusion in the HO2S harness connector
- High fuel system pressure-Refer to Fuel System Diagnosis .
- Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Fuel saturation of the evaporative emission (EVAP) canister
- Exhaust leaks near the HO2S
- Contaminated HO2S-Silicon
- If you find any of the above conditions, repair as necessary.
If all circuits test normal, test or replace the applicable HO2S.