Engine Coolant Temperature Sensor Description

PURPOSE
The engine coolant temperature sensor converts the coolant temperature into a voltage and inputs it to the engine control module, which then controls the fuel injection rate and fast idle speed when the engine is cold, based on the input signal.

OPERATION

Engine Coolant Temperature Sensor Temperature To Resistance Curve:

The 5 V power in the engine control module is supplied via a resistor in the module to the engine coolant temperature sensor. Via the sensor which is a kind of resistor, it is then grounded in the engine control module. The engine coolant temperature sensor resistor has such characteristic that its resistance decreases as the coolant temperature rises.

Engine Coolant Temperature Sensor Temperature To Voltage Curve:

The engine coolant temperature sensor terminal voltage increases or decreases as the sensor resistance increases or decreases. Therefore, the engine coolant temperature sensor terminal voltage changes with the coolant temperature, decreasing as the temperature rises.