HO2S Heater Resistance Inspection

1. Disconnect the HO2S connector.
2. Measure the HO2S resistance between terminals C and D.

• If not within the specification, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)

HO2S heater resistance 2-50 ohms 

Fig 1: Identifying HO2S Connector Terminals

Courtesy of MAZDA MOTORS CORP.