What is an ECT Sensor?

The ECT sensor is usually the Engine Coolant Temperature sensor. Most modern cars have such a sensor to advise the ECM/PCM about the operating temperature of the engine. Ford also uses a Cylinder Head Temperature sensor to detect overheating condition in the case of lost coolant..... The ETC, via the PCM, also controls the cold-start quantity of fuel required (given a specific temperature);.. in other words, it acts like a choke operation in cold weather!... I f malfubctioning, can cause prolonged cranking before engine start in cold weather.