Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block. Heated oxygen sensor No. 2 refers to sensor farthest from engine block.
Circuit Description
Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC P0136 is set when bank No. 1, sensor No. 2 voltage remains at .4 volt or more, or .5 volt or less during vehicle operation (31 MPH or more), once engine is at normal operating temperature. DTC P0156 is set when bank No. 2, sensor No. 2 voltage remains at .4 volt or more, or .5 volt or less during vehicle operation (31 MPH or more), once engine is at normal operating temperature. Possible cause is
- Defective heated oxygen sensor No. 2.
Diagnostic Aids
Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.