V70R AWD L5-2.3L Turbo VIN 52 B5234T6 (1998)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
ENGINE COOLANT TEMPERATURE SENSOR
The Engine Coolant Temperature (ECT) Sensor supplies the Engine Control Module (ECM) with a signal describing the temperature of the engine
coolant. This gives the engine coolant temperature (ECT) sensor a measurement of engine temperature and influences the control of:
^ Injection period
^ Idling speed
^ Engine Cooling Fan (FC)
^ Ignition timing
^ On-Board Diagnostic (OBD) functions.
The sensor incorporates a temperature-sensitive resistance with a Negative Temperature Coefficient (NTC). The sensor is supplied with a stabilized
voltage of 5 V from the engine control module (ECM).
The voltage across the sensor is a function of the engine temperature and, therefore, of sensor resistance. Voltage can vary between 0 V and 5 V.
The engine control module (ECM) uses substitute values if the signal from the engine coolant temperature (ECT) sensor is missing or faulty, however,
substitute values can cause starting problems in very cold weather.
The engine coolant temperature (ECT) sensor is mounted in the thermostat housing.