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 Engine Control Module (ECM). HO2S is located on exhaust pipe, behind catalytic converter. HO2S may also be referred to as oxygen sensor (bank No. 1 & 2, sensor No. 2). ECM uses input signals to determine fuel injection system operation. DTC is set when HO2S output voltage remains at 0.40 volt or more, or 0.50 volt or less when vehicle is driven at 31 MPH with engine at normal operating temperature. Possible causes are:
- HO2S circuit is open or shorted (bank 1 & 2, sensor 2).
- Defective HO2S (bank 1 & 2, sensor 2).
- Defective HO2S heater (bank 1 & 2, sensor 2).
- EFI relay defective.