Circuit Description
WARNING: This page is about a different car, the 2000 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
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 driven rich beyond a certain value. Possible causes are:
- Exhaust system leak.
- Improper fuel pressure.
- Fuel injector restricted.
- Defective heated oxygen sensor No. 1.
- Defective Manifold Absolute Pressure (MAP) sensor.
- Defective Engine Coolant Temperature (ECT) sensor.
DTC P0172 is set when fuel trim is driven lean beyond a certain value. Possible causes are:
- Exhaust system leak.
- Improper fuel pressure.
- Fuel injector blocked or leaking.
- Defective heated oxygen sensor No. 1.
- Defective Manifold Absolute Pressure (MAP) sensor.
- Defective Engine Coolant Temperature (ECT) sensor.