Oxygen Sensor: Testing and Inspection

HEATED OXYGEN SENSOR (FRONT REAR) TESTING
Using the SSTs (engine signal monitor)
1. Remove the PCM.

SSTs Engine Signal Monitor:

2. Connect the SSTs to the PCM.
3. Warm up the engine to normal operating temperature.
4. Measure the voltage at PCM terminals 3D, 3H, 3I and 3M.

5. If not as specified, inspect the following.
- Intake-air system
- Fuel system
- On-board diagnostic system
If these systems are OK, replace the heated oxygen sensor.

Tightening torque: 30-49 Nm (22-36 ft.lbs.)

Using the NGS

SST NGS:

1. Connect the Special Service Tools (SST)s New Generation Star (NGS) tester to the data link connector-2.

2. Select the PID/DATA MONITOR AND RECORD function of NGS.
3. Select "FHO2S R", "RHO2S R", "FHO2S L" and "RHO2S L" on the NGS display. NGS measures and shows the voltage.

4. If not as specified, inspect the following.
- Intake-air system
- Fuel system
- On-board diagnostic system
If these systems are OK, replace the heated oxygen sensor.

Tightening torque: 30-49 Nm (22-36 ft.lbs.)

HEATER TESTING
1. Disconnect the heated oxygen sensor connector.

HO2S Connector:

2. Measure the resistance between heated oxygen sensor (front) terminals B and C by using an ohmmeter. Measure the resistance between heated oxygen sensor (rear) terminals C and D by using an ohmmeter.

Specification: Approx. 6 Ohms @ 20°C (68°F)

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

Tightening torque: 30-49 Nm (22-36 ft.lbs.)