Rear HO2S Heater Resistance Inspection

Disconnect the rear HO2S connector.
Measure the rear HO2S resistance between terminals C and D.
- If not within the specification, replace the HO2S.
Rear HO2S heater resistance

2-50 ohms

Fig 1: Identifying Fuse HO2S Connector Terminals
Courtesy of MAZDA MOTORS CORP.