Front Heated Oxygen Sensor (Ho2S) Removal/Installation

Remove the battery cover.
Disconnect the negative battery cable. (See BATTERY REMOVAL/INSTALLATION [LF] .)
Install the SST to the front HO2S.
Remove the front HO2S.

Fig 1: Removing Front Heated Oxygen Sensor (HO2S)
Courtesy of MAZDA MOTORS CORP.
Install in the reverse order of removal.
Front HO2S tightening torque

29-49 N.m {3.0-4.9 kgf.m, 22-35 ft.lbf}