Engine Coolant Temperature (ECT) Sensor

Engine Coolant Temperature (ECT) sensor monitors coolant temperature. A 5-volt reference voltage is supplied and monitored by ECM. Sensor resistance, which changes according to coolant temperature, is converted to a temperature reading by ECM. High coolant temperature causes low resistance and low coolant temperature causes high resistance. The ECM uses this information for fuel control, timing, air management, idle speed and closed loop fuel control.