Repair procedures: Removal

Turn the ignition switch OFF and disconnect the battery negative (-) cable.
Disconnect the engine coolant temperature sensor connector (A).

Fig 1: Engine Coolant Temperature Sensor Connector And Component Location
Courtesy of KIA MOTORS AMERICA, INC.
Remove the fixing clip (A), and then pull the sensor from the water temperature control assembly.

Fig 2: Identifying Sensor Fixing Clip
Courtesy of KIA MOTORS AMERICA, INC.

CAUTION: Note that engine coolant may be flowed out from the water temperature control assembly when removing the sensor.
Supplement the engine coolant (Refer to COOLANT "Cooling System" in EM group).