Oxygen Sensor: Testing and Inspection

CAUTION: Before checking the Oxygen Sensor,
a. Run the engine until the engine coolant temperature has reached 185-205~F (85-95~C).
b. Use a digital voltmeter

1. Disconnect the Oxygen Sensor connector.

Oxygen Sensor Connector:

Oxygen Sensor Connector:

2. Using alligator clips connect the voltmeter positive lead to the electrical connector of the sensor, and the negative lead to ground.

NOTE: The Oxygen Sensor on California model vehicles use a two terminal connector.

3. While repeating engine racing, note the output voltage from the Oxygen Sensor.

NOTE: Output voltage should be approximately 1 volt. If not, use an alternative method for enriching the air/fuel mixture, then retest.

4. Replace the sensor if the tests results indicate a malfunction.
Refer to COMPONENT REPLACEMENT AND REPAIR PROCEDURES.