Circuit/System Testing
- Verify that none of the following conditions exist:
- Lean or rich fuel injectors-Refer to Fuel Injector Balance Test with Special Tool .
- Water intrusion in the HO2S harness connector
- HO2S wiring harness damage
- Incorrect RTV sealant
- Low or high 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) .
- Fuel saturation of the evaporative emission (EVAP) canister
- Exhaust leaks near the HO2S
- Engine vacuum leaks
- Engine oil consumption
- Engine coolant consumption-Refer to Loss of Coolant .
- If you find any of the above conditions, repair as necessary.
- If all conditions test normal, replace the appropriate HO2S.