Oxygen Sensor: Testing and Inspection

Fig. 54 Oxygen Sensor Test Connection:

NOTE: The following LH-Jetronic system troubleshooting procedures should only be conducted after it has been determined that the engine, charging system and ignition system are in satisfactory operating condition, and all electrical connectors and vacuum hoses have been checked for proper connection and routing.

1. Loosen two pin connector from wiring harness.
2. Using a multimeter, check resistance between the two white colored connectors on the oxygen sensor, Fig. 54. Resistance reading obtained should be approximately 4 ohms. This test will verify that the pre-heater circuit within the sensor is within specification.
3. Set multimeter to the 2 volt scale and connect between black oxygen sensor lead and ground. Start engine. As the sensor reaches a predetermined operating temperature, it will begin to generate a low voltage signal between 0.1 and 0.9 volts. The signal will change as the fuel mixture changes, a rich mixture giving a higher voltage reading and a lean mixture giving a lower voltage reading.