The Air Fuel Ratio AF sensor has an output delay of a few seconds and the Heated Oxygen HO sensor has a maximum output delay of approximately seconds

Case

A/F Sensor (Sensor 1) Output Voltage

HO2 Sensor (Sensor 2) Output Voltage

Main Suspected Trouble Area

Output Voltage More than 3.35 V Less than 3.0 V

Output Voltage More than 0.55 V Less than 0.4 V

Output Voltage Almost no reaction

Output Voltage More than 0.55 V Less than 0.4 V

A/F sensor A/F sensor heater A/F sensor circuit

Case

A/F Sensor (Sensor 1) Output Voltage

HO2 Sensor (Sensor 2) Output Voltage

Main Suspected Trouble Area

Output Voltage More than 3.35 V Less than 3.0 V

Output Voltage Almost no reaction

HO2 sensor HO2 sensor heater HO2 sensor circuit

Output Voltage Almost no reaction

Output Voltage Almost no reaction

Fuel injector Fuel pressure Gas leakage from exhaust system (Air fuel ratio extremely lean or rich)

• Following the A/F CONTROL procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.

• To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2, and press the YES button and then the ENTER button followed by the F4 button.

HINT:

• If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.

• Read freeze frame data using an intelligent tester. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

• If the OX1B wire from the ECM connector is short-circuited to the +B wire, DTC P0136 will be set.

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