Heated Oxygen Sensor Testing

SENSOR INSPECTION
- Warm up the engine to normal operating temperature.
- Connect the SSTs (Engine Signal Monitor) to the PCM.




- Measure the PCM terminal 3C and 3D voltages.

- If not as specified, inspect the following.







- Harness and connector between heated oxygen sensor and PCM.
- On-board diagnostic system
- System inspection
Intake manifold vacuum
Fuel line pressure
- If all the systems are OK, replace the heated oxygen sensor.

USING THE NGS
- Connect the SSTs (NGS) to the data link connector-2.




- Select the PID/DATA MONITOR AND RECORD function.




- Select "FHO2S", "RHO2S" on the NGS display. The NGS measures and shows the voltage.
- If not as specified, inspect the following.
- Harness and connector between heated oxygen sensor and PCM.
- On-board diagnostic system
- System inspection
Intake manifold vacuum
Fuel line pressure
- If all the systems are OK, replace the heated oxygen sensor.

HEATER INSPECTION
- Disconnect the heated oxygen sensor connector.
- Measure the resistance between heated oxygen sensor terminals D and C by using an ohmmeter.

Specification:
Approx. 13 ohms @ 20°C (68°F) (Front)
Approx. 6 ohms @ 20°C (68°F) (Rear)

- If not as specified, replace the heated oxygen sensor.