Front HO2S Heater Resistance Inspection

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

Fig 1: Identifying Front HO2S Terminals
Courtesy of MAZDA MOTORS CORP.
- If not within the specification, replace the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
Front HO2S heater resistance

1-10 ohms