HO2S Heater Inspection

1. Remove the battery cover. (See BATTERY REMOVAL/INSTALLATION .)
2. Disconnect the negative battery cable. (See BATTERY REMOVAL/INSTALLATION .)
3. Disconnect the HO2S connector.
4. Measure the resistance between HO2S terminals C and D.

Courtesy of MAZDA MOTORS CORP.

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

HO2S heater resistance 

2-50 ohms [normal temperature]