DTC P0136 & DTC P0156 Lexus ES XV30

Code Definitions

1. DTC P0136: Heated Oxygen Sensor Circuit Malfunction (Bank No. 1, Sensor No. 2)
2. DTC P0156: Heated Oxygen Sensor Circuit Malfunction (Bank No. 2, Sensor No. 2)

Note. Bank No. 1 refers to bank which includes cylinder No. 1.

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. ECM uses input signal to determine fuel injection system operation. DTC is set when oxygen sensor remains at .35 volt or more, or .55 volt or less during vehicle operation once engine is at normal operating temperature. Possible causes are

1. Defective heated oxygen sensor.
2. Fuel trim malfunction.

Diagnostic Aids

Using scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.