Circuit Description
Fuel trim refers to feedback compensation value compared against basic injection time. Fuel trim includes short-term and long-term fuel trim.
DTC P0174 is set when fuel trim is driven rich beyond a certain value with engine at normal operating temperature and the actual air/fuel ratio is lean. Possible causes are:
- Air induction system malfunction.
- Fuel injector restricted.
- Defective Mass Airflow (MAF) meter.
- Defective Engine Coolant Temperature (ECT) sensor.
- Ignition system malfunction.
- Improper fuel pressure.
- Exhaust system leak.
- Air/Fuel (A/F) sensor (bank No. 2, sensor No. 1) circuit is open or shorted.
- Defective A/F sensor (bank No. 2, sensor No. 1).
- Defective ECM.
- Vehicle ran out of fuel.
DTC P0175 is set when fuel trim is driven lean beyond a certain value with engine at normal operating temperature and the actual air/fuel ratio is rich. Possible causes are:
- Air induction system malfunction.
- Fuel injector restricted or leaking.
- Defective Mass Airflow (MAF) meter.
- Defective Engine Coolant Temperature (ECT) sensor.
- Ignition system malfunction.
- Improper fuel pressure.
- Exhaust system leak.
- Air/Fuel (A/F) sensor (bank No. 2, sensor No. 1) circuit is open or shorted.
- Defective A/F sensor (bank No. 2, sensor No. 1).
- Defective ECM.
- Vehicle ran out of fuel.