Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. Heated oxygen sensor No. 2 may be referred to as (bank No. 1 sensor No. 2) and is located on exhaust pipe behind catalytic converter. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC is set when heated oxygen sensor No. 2 voltage remains at .35 volt or more, or .55 volt or less during vehicle operation (25 MPH or more), once engine is at normal operating temperature, or voltage amplitude is less then .3 volts. Possible cause is
- Heated oxygen sensor No. 2 circuit is open or shorted.
- Defective heated oxygen sensor No. 2.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.