Water Temperature Sensor (WTS): Description
WARNING: This page is about a different car, the 2004 Kia Amanti. However, it is still accessible from the selected car via links, so may be relevant.
Water Temperature Sensor (WTS), installed in the engine coolant passage of the cylinder head, detects the engine coolant temperature and emits signals to the ECU. This part employs a thermistor which is sensitive to changes in temperature. The electric resistance of the thermistor decreases in response to a temperature rise (NTC). The ECU determines engine coolant temperature by the sensor output voltage and provides optimum fuel enrichment when the engine is cold.