Circuit Description
WARNING: This page is about a different car, the 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
For circuit description, see Circuit Description under DTCs P0031, P0032, P0051 & P0052. DTC is set when engine is warmed up, vehicle is driven at engine speed of 1400 RPM or more and vehicle speed is 38 MPH or more. In this condition, air/fuel ratio sensor output voltage change value is below regular value against fuel trim change value. ECM judges that air/fuel ratio sensor circuit has slow response. Possible causes are:
- A/F ratio sensor circuit is open or shorted.
- Defective A/F ratio sensor.
- Defective A/F sensor heater.
- Defective A/F ratio sensor heater relay.
- Defective A/F ratio sensor heater and relay circuit.
- Faulty air induction system.
- Faulty fuel pressure.
- Faulty injector.
- Defective ECM.