Heated Oxygen Sensor Heater On-Vehicle Inspection

Disconnect HO2S-1 or HO2S-2 coupler.
Using ohmmeter, measure resistance between terminals "VB" and "GND" of HO2S coupler (1). If found faulty, replace HO2S.
NOTE: Temperature of HO2S affects resistance value largely.

Make sure that HO2S heater is at correct temperature.

Resistance of HO2S heater
1. HO2S-1: 5.0 - 6.4 ohm at 20°C (68°F)
2. HO2S-2: 11.7 - 14.3 ohm at 20°C (68°F)
Fig 1: Measuring Resistance Between Terminals
Courtesy of SUZUKI OF AMERICA CORP.
Connect HO2S coupler securely.