Computer Command Control - Port Fuel Injection

Engine Coolant Temperature Sensor:

The engine coolant temperature sensor is a thermistor that is located in the engine coolant flow. When the coolant temperature is low, the sensor produces a high resistance. When the coolant temperature is high, the sensor produces a low resistance.

The ECM sends a 5.0 volt signal to the coolant temperature sensor through a resistor in the computer and measures the voltage. The voltage will be high or low depending on coolant temperature. By varying the voltage the computer will sense engine coolant temperature.