Possible Causes

Malfunction is detected when mixture ratio compensation amount is too large (mixture is too lean or too rich). Possible causes are:

• Defective HO2S1.
• Defective injectors.
• Exhaust leaks.
• Fuel pressure incorrect.
• Defective Mass Airflow (MAF) sensor.
• Lack of fuel (DTC P0171 or DTC P0174 only).
• Intake air leaks (DTC P0171 or DTC P0174 only).