The engine coolant temperature sensor is a negative temperature coefficient (NTC) thermistor. It is of a similar type to the air temperature sensor. It is fitted into the water jacket close to the thermostat or bypass coolant circuit passages. The sensor measures the engine coolant temperature and provides a signal voltage to the ECU. This is used for cold-start and warm-up enrichment as well as fast idle speed control through the idle speed control valve.
2015 Porsche 918 Spyder
T - Coolant temperature sensor
The temperature sensor for the coolant is in the upper part of the crankcase, near the cylinder head gasket face of cylinder 9.