Circuit Description
WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC is set when heated oxygen sensor No. 1 does not output a rich condition once engine is at normal operating temperature, engine speed of more than 1500 RPM and vehicle speed is 25-62 MPH for at least 1.5 minutes. Possible causes are:
- Heated oxygen sensor No. 1 circuit is open or shorted.
- Defective heated oxygen sensor(s) No. 1.
- Leaking air intake system.
- Fuel pressure problem.
- Defective fuel injector.
- Exhaust system leak.
- Defective ECM.
- PVC piping.