Sensor ECT engine coolant temp.

ECT

With the ignition switched to "ON" back probing the ECT sensor with a mutli meter on volts while the engine was cold i got a reading of 4v, 5 after letting the engine run for minutes having taken anouther reading of 0.025v

This shows how the colder the engine is the higher the voltage output will be... Around 0.01v the engine temp. is at a perfect operating temp. around 115*c (220 F)

ECM also relays on the temperature of the engine coolant to determine if the engine is at operating temerature, the voltage changes due to the temperature being colder or hotter,

cold coolant indicated by less than 0.4 hot coolant the voltage sits around 4-5v good operating temp.