In-Vehicle Temperature Sensor

In-vehicle Temperature Sensor

The in-vehicle temperature sensor is an encapsulated NTC (negative temperature coefficient) thermistor that provides the ATC (automatic temperature control) module with an input of passenger compartment air temperature. The in-vehicle temperature sensor is installed behind a grille in the ATC (automatic temperature control) module control panel. An electric fan in the ATC (automatic temperature control) module runs continuously, while the ignition is on, to draw air through the grille and across the in-vehicle temperature sensor.

The ATC (automatic temperature control) module uses the signal from the in-vehicle temperature sensor for control of the coolant temperature valve(s), blower speed and air distribution.

The signal voltage from the in-vehicle temperature sensor is between 0 and 5 V. The ATC (automatic temperature control) module monitors the signal voltage and defaults to a temperature of 20 degrees C (68 degrees F) if it goes out of the range 0.573 - 4.882 V:
^ If the signal voltage is less than 0.573 V, the ATC (automatic temperature control) module assumes there is a short circuit to ground.
^ If the signal voltage is more than 4.882 V, the ATC (automatic temperature control) module assumes there is an open circuit or a short circuit to battery.