Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la
If it fails: lemon-manuals.org.ua

Or, hide this message: temporarily or permanently

Engine Coolant Temperature Sensor - Operation






OPERATION

The coolant temperature (ECT) sensor is a negative temperature coefficient (NTC) thermistor (resistance varies inversely with temperature). This means at cold temperatures its resistance is high so the voltage signal will be high. As coolant temperature increases, resistance decreases and the signal voltage will be low. This allows the sensor to provide an analog voltage signal to the ECM.