Engine Coolant Temperature Sensor (ECTS)

Specifications

Specification

Engine Coolant Temperature Sensor (ECTS)

▷ Type: Thermistor Type

Description and Operation

Description

The Engine Coolant Temperature Sensor (ECTS) is installed in the cylinder head coolant passage to detect engine coolant temperature. The ECTS uses a thermistor whose resistance changes according to temperature.

The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. A reference +5V is supplied to the ECTS through a resistor in the ECM. In other words, the resistor in the ECM and the thermistor in the ECTS are connected in series. When the resistance of the thermistor in the ECTS changes according to the engine coolant temperature, the output voltage also changes.

When the engine is cold, the ECM increases the fuel injection duration and controls ignition timing using the engine coolant temperature information to prevent engine stalling and improve drivability.

Circuit Diagrams

Wiring Diagram

Repair Procedures

Inspection

1. 1

   Turn the ignition off.

2. 2

   Disconnect the ECTS connector.

3. 3

   Remove the ECTS.

4. 4

   After immersing the sensor thermistor in engine coolant, measure the resistance between ECTS terminals 1 and 2.

   

5. 5

   Make sure the resistance is within specification.

   Temperature		Resistance (kOhm)
   °C	°F
   -40	-40	48.14
   -20	-4	14.13-16.83
   0	32	5,79
   20	68	2,31-2,59
   40	104	1,15
   60	140	0,59
   80	176	0,32
   100	212	0,19
   110	230	0,145 ~ 0,149
   120	248	0,12

Removal

1. 1

   Turn the ignition switch OFF and disconnect the negative (-) battery terminal.

2. 2

   Disconnect the engine coolant temperature sensor connector (A).

3. 3

   Remove the retaining clip (B), then pull the sensor out of the water temperature control assembly.

   

   

4. 4

   Refill the engine coolant.

   (Refer to Engine Mechanical System - Engine Coolant)

Installation

1. Installation is the reverse of removal.