Oxygen Sensor Heater Inspection (Sensor 1 and 2)

1. Disconnect oxygen sensor coupler.
2. Using ohmmeter, measure resistance between terminals "V(B)" 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:
11.7 - 14.3 Ohm (at 20 °C, 68 °F) for HO2S-1 without WU-TWC and sensor-2
4.5 - 5.7 Ohm (at 20 °C, 68 °F) for HO2S-1 with WU-TWC

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