Oxygen Sensor Test
- Remove 2-pin oxygen sensor connector from wiring harness socket. Connect ohmmeter across White leads of oxygen sensor to check resistance of oxygen sensor heating element. Resistance should be about 4 ohms.
- Connect voltmeter (set on 2 volt scale) between Black lead of sensor and ground. Start engine. As engine temperature begins to rise, sensor will generate a low voltage signal.
- A lean mixture (caused by a small vacuum leak) will generate a voltage reading close to zero volts. A rich mixture will generate a voltage reading close to one volt. Reconnect sensor leads.