ECT Sensor No. 1

Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION ).
Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT ).
Disconnect the ECT sensor No. 1 connector.
Remove the ECT sensor No. 1 using the SST.

Fig 1: Removing ECT Sensor No. 1
Courtesy of MAZDA MOTORS CORP.
Install in the reverse order of removal.
Refill the engine coolant. (See ENGINE COOLANT REPLACEMENT ).