Circuit/System Verification
- Ignition ON, observe the scan tool DTC information. Verify there are no other DTCs set.
- If there are other DTCs set refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
- Engine at normal operating temperature, observe the scan tool Total Fuel Trim Avg. parameter. The parameter should display between -22 to +23 percent.
- If not within the specified range, verify that none of the following conditions exist:
- A mass air flow (MAF) sensor signal that is skewed-If the Short Term FT parameters for both banks changes greater than 20 percent when the MAF sensor is disconnected, refer to DTC P0101 for further diagnosis.
- Inspect the HO2S 1 and HO2S 2 for being secure
- Damaged wiring between either HO2S and the ECM
- Inspect the throttle body and the intake manifold for vacuum leaks
- Inspect for exhaust leaks, missing or loose exhaust hardware.
- Inspect the crankcase ventilation system for leaks
- Lean fuel injectors-Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2
- Incorrect 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)
- Contaminated HO2S-Silicon
- Inspect for a high engine oil level condition. A high engine oil level causes oil residue to form on the MAF sensor, causing a lean indication. The MAF sensor does not need to be replaced
- If not within the specified range, verify that none of the following conditions exist:
- 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 are captured in the Freeze Frame/Failure Records Data List.