Oxygen Sensor: Testing and Inspection

Fig. 10 Testing oxygen sensor.:

1. Run engine until normal operating temperature is reached and continue to run at idle.
2. Disconnect electrical connector from oxygen sensor, Fig. 1.
3. Attach a voltmeter between oxygen sensor side of electrical connector and ground.
4. Run engine at 4000 RPM until voltmeter indicates approximately .7 volt.
5. Quickly accelerate and decelerate engine several times. Voltmeter should indicate .5---1.0 volt when engine speed is increased and 0---.3 volt when engine speed is decreased.
6. If operation is not as described, replace oxygen sensor.