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

Disconnect A/F sensor connector.
Using ohmmeter, measure resistance of Sensor heater between terminals "V_B " 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 Ω at 20°C (68°F)

Fig 1: Identifying Air Fuel Ratio (A/F) Sensor Connector Terminal
Courtesy of SUZUKI OF AMERICA CORP.
Connect A/F sensor connector securely.