Oxygen Sensor: Testing and Inspection

1. Warm up the engine and run it at idle.
2. Disconnect the oxygen sensor wiring harness connector.

Oxygen Sensor Inspection:

3. Connect a voltmeter between the oxygen sensor connector (oxygen sensor side) and ground.
4. Increase and decrease the engine speed suddenly several times. When the speed is increased check that the voltmeter reads between 0.5 and 1.0 volts. When the speed is decreased check that the voltmeter reads between 0 and 0.4 volts. Reconnect the oxygen sensor connector.
5. If not as specified, replace the oxygen sensor.

Self-Diagnostic Checker Connected To Check Connector:

6. Connect the self diagnostic tester to the check connector and the negative battery terminal.

NOTE: Do not ground the test connector (Green:1-pin) during this test.

Self Diagnostic Checker:

7. Increase the engine speed to between 2,000 and 3,000 rpm and check that the monitor lamp flashes for 10 seconds. It should flash eight or more times in the ten second period. Disconnect the diagnostic tester.