Replacing the coolant temperature sensor (ECT Sensor)

The coolant temperature sensor (ECT sensor) sends engine temperature data to the vehicle's engine control module. This information is used to manage fuel injection, engine operation, cooling fan activation, and the temperature display on the dashboard. Over time the sensor may fail, send incorrect readings, or stop functioning completely. Common symptoms include incorrect temperature readings, increased fuel consumption, rough operation during cold starts, or cooling fan activation problems. Mechanics diagnose the cooling system, verify the temperature sensor signal through diagnostic equipment, and replace the ECT sensor when necessary. Access to the sensor can vary depending on engine design, so replacement may be straightforward on some vehicles while others may require partial disassembly of cooling system components.