Oxygen Sensor: Testing and Inspection

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






3. Connect a voltmeter between the heated oxygen sensor connector (A) and (B) (heated oxygen sensor side).
4. Increase and decrease the engine speed suddenly several times. When the speed is increased, check that the meter reads between 0.5 V-1.0 V.
When the speed is decreased, check that it reads between 0 V-0.5 V.
5. If not as specified, replace the heated oxygen sensor.

Inspection Of Sensitivity
1. Warm up the engine to normal operating temperature.






2. Connect the SSTs (Special Service Tools) (System Selector and Self-Diagnosis Checker) to the data link connector as shown.
3. Set the switch (A) to position 1.
4. Set TEST switch to O2 MONITOR.






5. Increase the engine speed to between 2,000 and 3,000 rpm, and verify that the monitor lamp flashes for 10 seconds at the specified rate.

Monitor Lamp: Flashes more than 4 times/1O sec.

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







Inspection Of Heater
1. Disconnect the connector of heated oxygen sensor wiring harness.
2. Connect an ohmmeter between (D) and (C) terminals (heated oxygen sensor side) and check for continuity.
3. If there is no continuity, replace the heated oxygen sensor.