Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

ENGINE COOLANT TEMPERATURE SENSOR (ECTS)




DESCRIPTION
The engine coolant temperature sensor (ECTS) is located in the engine coolant passage of the cylinder head for detecting the engine coolant temperature. The ECTS uses a thermistor whose resistance changes with the temperature variation. The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. When the resistance value of the thermistor in the ECTS changes according to the engine coolant temperature, the output voltage also changes. During cold engine operation the ECM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve driveability.

Circuit Diagram:

CIRCUIT DIAGRAM

SENSOR INSPECTION
1. Remove the Engine Coolant Temperature Sensor (ECTS) from the engine block.




2. With the temperature sensing portion of Engine Coolant Temperature Sensor (ECTS) immersed in hot engine coolant, measure resistance between the terminals 1 and 3 of ECTS connector.
3. If the resistance deviates from the standard value greatly, replace the sensor.

HARNESS INSPECTION
Refer to DTC P0117 and P0118 troubleshooting procedures.

INSTALLATION
1. Apply sealant LOCTITE 962T or the equivalent to the threaded portion.
2. Install the ECTS and tighten it to the specified torque.

Tightening torque : 3.0 - 4.0 kgf.m

3. Securely connect the harness connector.