An engine coolant temperature (ECT) sensor is a device that measures the temperature of the coolant in an internal combustion engine. This information is used by the engine’s electronic control unit (ECU) to adjust the engine’s air/fuel mixture, ignition timing, and other parameters.
If the ECT sensor fails, it can cause the engine to run poorly, or not at all. In some cases, a failed ECT sensor can also cause the engine to overheat. To reset an ECT sensor, you will need to: