Possible Causes
WARNING: This page is about a different car, the 2002 Nissan Pathfinder and 2002 Infiniti QX4. However, it is still accessible from the selected car via links, so may be relevant.
ECM illuminates MIL and sets DTC P0171 when Bank 1 fuel mixture ratio compensation amount is too large (mixture is too lean).
ECM illuminates MIL and sets DTC P0174 when Bank 2 mixture ratio compensation amount is too large (mixture is too lean). Possible causes are:
- Intake air leaks.
- Poor, loose, corroded or damaged terminal connections.
- Defective HO2S 1.
- Defective injectors.
- Exhaust leaks.
- Fuel pressure incorrect.
- Lack of fuel.
- Defective MAF sensor.