Current Sensor Removal

Disconnect the current sensor connector.
Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5] .)
Loosen the current sensor nut while fixing the negative battery terminal using a wrench.

Fig 1: Loosening Current Sensor Mounting Nut Using Tool
Courtesy of MAZDA MOTORS CORP.
Remove the current sensor.

Fig 2: Identifying Current Sensor Components
Courtesy of MAZDA MOTORS CORP.