Oxygen Sensor: Testing and Inspection

Voltmeter:

Sensor Replacement:

INSPECTION
1. Warm up the engine to normal operating temperature and run at idle.
2. Using a volt meter, measure the voltage at PCM terminals C254-2 (front sensor) and C254-10 (rear sensor).
3. Increase and decrease the engine speed suddenly several times.
4. Verify that when the speed is increased, the meter reads 0.5 - 1 .0V (both terminals), and when the speed is decreased it reads 0 - 0.5V (both terminals)
5. If not as specified, repeat the voltage check at the suspected faulty heated oxygen sensor.
6. If still not as specified, replace the heated oxygen sensor.


REPLACEMENT
1. Disconnect the heated oxygen sensor connector.

WARNING: The oxygen sensor will be very hot when engine has been operated.

2. Remove the heated oxygen sensor.
3. Install in the reverse order of removal.

Tighten
Sensor to 22 - 36 ft lb (29 - 49 Nm)

Connector View:

HEATED OXYGEN SENSOR HEATER
1. Ensure that the ignition switch is OFF.
2. Disconnect the heated oxygen sensor connector from the .
3. Connect an ohmmeter between terminals 2 and 3 of the connector and measure the resistance.

Resistance: Approximately 6 ohms [68°F (20°C)]

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