Oxygen (O2) Sensor
- Turn ignition off. Disconnect 2-wire O2 sensor connector. Sensor is threaded into exhaust manifold. Measure resistance between 2 White wires. Resistance should be about 4 ohms.
- Connect DVOM leads between Black sensor wire and ground. Start engine. With sensor at operating temperature, voltage should fluctuate between 0.1 and 0.9 volt. Replace O2 sensor if resistance or voltage is not as specified.