Circuit Description
WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
Heated oxygen sensor No. 1 monitors exhaust gas oxygen content and delivers input signals to ECM. Heated oxygen sensor No. 1 is located on exhaust pipe in front of catalytic converter and may also be referred to as bank No. 1, sensor No. 1, or front oxygen sensor. ECM uses input signals to determine fuel injection system operation. DTC is set when heated oxygen No. 1 response time for the output voltage to change from rich to lean, or from lean to rich is .4 second or more during constant vehicle speeds with engine at normal operating temperature. Possible causes are:
- Heated oxygen sensor No. 1 circuit is open or shorted.
- Defective heated oxygen sensor No. 1.
- Air induction system malfunction.
- Improper fuel pressure.
- Defective fuel injector.
- Defective ECM.