Circuit/System Verification
WARNING: This page is about a different variant/trim than selected.
- Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description .
- Ignition ON, verify the scan tool hood position parameter displays Open.
- If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.
- Observe the DTC information with a scan tool. Verify no HO2S heater DTCs are set.
- If any HO2S heater DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Verify none of the following conditions exist:
- Lean or rich fuel injectors-Refer to Fuel Injector Diagnosis (CH47976) , Fuel Injector Diagnosis (J39021 or Scan Tool)
- Water intrusion in the HO2S harness connector
- Low or high 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
- Fuel saturation of the evaporative emission (EVAP) canister
- Exhaust leaks near the HO2S
- Engine vacuum leaks
- Engine oil consumption-Refer to Oil Consumption Diagnosis
- Engine coolant consumption-Refer to Loss of Coolant
- If you find any of the above conditions, repair as necessary.
- If all conditions test normal, test or replace the appropriate HO2S.
- 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.