The Coolant Temperature Sensor detects the temperature of the engine coolant. This sensor is located on the engine or in one of the coolant passages in the cylinder head. 

Features & Benefits: 

It senses changes in coolant temperature, which gives the ECU vital information to help control fuel injection, ignition timing and transmission shifting.

A failing sensor can cause the engine to run rich or lean, cause the transmission to shift incorrectly, or cause the Check Engine Light to illuminate.