Air Fuel Ratio (A/F) Sensor On-Vehicle Inspection

Air Fuel Ratio (A/F) Sensor On-Vehicle Inspection

Heater

1) Disconnect A/F sensor connector.
2) Using ohmmeter, measure resistance of sensor heater between terminals "VB" and "GND" at sensor connector. If found faulty, replace A/F sensor.

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

A/F sensor heater resistance
2 - 3 ohms at 20 °C (68 °F)

Viewed from terminal side





3) Connect A/F sensor connector securely.