Circuit Description
WARNING: This page is about a different car, the 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
The oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses this input signal to determine fuel injection system operation. Sensors include heater. DTC P0125 is set when sensor does not output a rich condition once engine is at normal operating temperature, engine speed is 1400 RPM or more, vehicle speed is at 25-62 MPH, throttle valve is not fully closed, and at least 180 seconds have elapsed since engine has been started, for at least 1.5 minutes. DTC P0125 is also set when vehicle runs out of fuel. Possible causes are:
- Open or short in oxygen sensor circuit.
- Faulty heated oxygen sensor.
- Faulty air induction system.
- Fuel system pressure fault.
- Fuel injectors.
- Exhaust leaks.
- Faulty ECM.