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 P0171 is set when fuel trim is rich beyond a certain value. Possible causes are:
- Air intake hose loose.
- Fuel line pressure.
- Injector blockage.
- Heated oxygen sensor.
- Manifold Absolute Pressure (MAP) sensor.
- Engine Coolant Temperature (ECT) sensor.
DTC P0172 is set when fuel trim is lean beyond a certain value. Possible causes are:
- Fuel line pressure.
- Injector blockage or leak.
- Heated oxygen sensor.
- Manifold Absolute Pressure (MAP) sensor.
- Engine Coolant Temperature (ECT) sensor.
NOTE:
Sensor No. 1 refers to sensor closest to engine block. Sensor No. 2 refers to sensor furthest from engine block.