AIR FUEL RATIO (A/F) SENSOR INSPECTION

Note

• Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See Troubleshooting Procedure.)

A/F Sensor Current Inspection

1. Warm up the engine to normal operating temperature.

2. Using the WDS or equivalent, verify that the current of the A/F sensor (WDS PID: O2S11) is as indicated in the table.

• If it cannot be verified even though the related harnesses have no malfunction, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION.)

A/F sensor current

Engine condition	Current
Accelerated	Negative value
Decelerated	Positive value

A/F Sensor Heater Resistance Inspection

1. Disconnect the A/F sensor connector.

2. Measure the resistance between A/F sensor terminals C and D.

• If not within the specification, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION.)

2.16-2.90 ohms [20 °C {68 °F}]

Circuit Open/Short Inspection

1. Disconnect the PCM connector.

2. Disconnect the A/F sensor connector.

3. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)

Open circuit

• If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.

- A/F sensor terminal A and PCM terminal 2B

- A/F sensor terminal B and PCM terminal 2C

- A/F sensor terminal C and main relay terminal C

- A/F sensor terminal D and PCM terminal 1V

Short circuit

• If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness.

- A/F sensor terminal A and body ground

- A/F sensor terminal A and power supply

- A/F sensor terminal B and body ground

- A/F sensor terminal B and power supply

- A/F sensor terminal D and body ground