KIA Niro: Engine Coolant Temperature Sensor (ECTS)

Specification

Description

Located in the engine coolant passage of the cylinder head, Engine Coolant Temperature Sensor
(ECTS) detects the engine coolant temperature. The ECTS uses a thermistor with resistance in
proportion to the temperature.

The electrical resistance of the ECTS decreases as the temperature increases, and increases as the
temperature decreases. The reference +5V is supplied to the ECTS via a resistor in the ECM. That is,
the resistor in the ECM and the thermistor in the ECTS are connected in series. 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 frequency of fuel injection and controls the
ignition timing using the information of engine coolant temperature to avoid engine stalling and
improve drivability.

Circuit
Diagram

ECTS (Water Temperature Control Assembly)

Harness Connector

ECTS (EGR Cooler Tube)

Harness Connector

Engine Coolant Temperature Sensor (ECTS) Repair procedures

Inspection

1. Switch "OFF" the ignition.
2. Remove the ECTS
   (Refer to "Removal").
3. After immersing the thermistor of the sensor into engine coolant, measure resistance between the ECTS terminals 1 and 2.
4. Check that the resistance is within the specification.

Removal

Engine Coolant Temperature Sensor (ECTS) (Water Temperature Control Assembly)

1. Switch "OFF" the ignition and disconnect the negative (-) battery terminal.
2. Remove the air cleaner assembly.

   (Refer to Engine Mechanical System - "Air Cleaner")

3. Remove the purge control solenoid valve.

   (Refer to Engine Control / Fuel System - "Purge Control Solenoid Valve (PCSV)")

4. Disconnect the engine coolant temperature sensor connector (A).
5. Remove the spring clip (B), and then pull the sensor from the water temperature control assembly.

Warning

Note that engine coolant may flow out from the water temperature control assembly when
removing the sensor.

Engine Coolant Temperature Sensor (ECTS) (EGR Cooler Tube)

1. Switch "OFF" the ignition and disconnect the negative (-) battery terminal.
2. Remove the air cleaner assembly.

   (Refer to Engine Mechanical System - "Air Cleaner")

3. Disconnect the engine coolant temperature sensor connector (A).
4. Remove the spring clip (B), and then pull the sensor from the water temperature control assembly.

Warning

Note that engine coolant may flow out from the water temperature control assembly when
removing the sensor.

Installation

Warning

• Install the component to the specified torque.
• Note that internal damage may occur when the component is dropped. If the component has been dropped, inspect before installing.
• Apply the engine coolant to the O-ring.
• Insert the sensor in the installation hole and be careful not to damage it.

1. Install in the reverse order of removal.
2. Replenish the engine coolant.

   (Refer to Engine Mechanical System - "Coolant")

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