Front HO2S Heater Resistance Inspection

Disconnect the front HO2S connector.
Measure the resistance between front HO2S terminals 2B and 2D.
- If not within the specification, replace the front HO2S. (See EXHAUST SYSTEM REMOVAL/INSTALLATION ).
Front HO2S heater resistance

1-10 ohms

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