Oxygen Sensor: Testing and Inspection

Measuring Oxygen Sensor Heater Resistance:

- Disconnect sensor coupler.
- Using ohmmeter, measure resistance between terminals "VB" and "GND" of sensor coupler.

NOTE:Temperature of sensor affects resistance value largely. Make sure that sensor heater is at correct temperature.

Resistance of oxygen sensor heater:
1993 California vehicle
11.7-15.5 ohms @ 20°C, 68°F
Other vehicles
3.7-5.1 ohms @ 23°C, 73°F


- If found faulty, replace oxygen sensor.
- Connect sensor coupler securely.