Circuit Description
WARNING: This page is about a different car, the 2003 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
Heated Oxygen Sensor (HO2S) monitors exhaust gas oxygen content and delivers input signals to ECM. HO2S is located on exhaust pipe in front of catalytic converter. ECM uses input signals to determine fuel injection system operation. DTC is set when response of oxygen sensor becomes deteriorated when vehicle is being driven at 38 MPH or more with engine at normal operating temperature and engine speed of 1400 RPM or more. Possible causes are:
- HO2S circuit is open or shorted.
- Defective HO2S.
- Air induction system malfunction.
- Improper fuel pressure.
- Defective fuel injector.
- Vehicle has run out of fuel.
- Defective ECM.