Circuit/System Verification
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- Ignition ON, observe the scan tool DTC information. Verify there is no other HO2S or fuel trim DTC set.
- If any other HO2S or fuel trim DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Verify that none of the following conditions exist:
- Exhaust system leaks-Refer to Symptoms - Engine Exhaust
- Vacuum hoses for splits, kinks, and proper connections
- Insufficient fuel in the tank
- The air induction system and the air intake ducts for leaks or for a missing air filter element
- A cracked evaporative canister
- Evaporative pipes plugged, obstructed, or leaking
- The crankcase ventilation system for leaks. Refer to Crankcase Ventilation System Inspection/Diagnosis
- Engine vacuum leaks
- 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 .
- Lean fuel injectors-Refer to Fuel Injector Diagnosis (CH47976) , Fuel Injector Diagnosis (J39021 or Scan Tool) .
- If you find any of the above conditions, repair as necessary.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.