ENGINE COOLANT TEMPERATURE SENSOR (ECTS)

Description and Operation

Description

The Engine Coolant Temperature Sensor (ECTS) is located in the engine coolant passage of the cylinder head to detect engine coolant temperature. The ECTS uses a thermistor whose resistance changes with temperature. The electrical resistance of the ECTS decreases as temperature rises and increases as temperature falls. A 5 V reference signal is supplied to the ECTS from the ECM through a resistor in the ECM. This means the resistor in the ECM and the thermistor in the ECTS are connected in series. When the thermistor resistance in the ECTS changes with engine coolant temperature, the output voltage also changes. When the engine is cold, the ECM increases fuel injection duration and controls ignition timing using the engine coolant temperature information to prevent engine stalling and improve drivability.

Specifications

Specification

TEMPERATURE		RESISTANCE (kΩ)
°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

Circuit Diagrams

Wiring Diagram

(B)

(MT)

Repair Procedures

Inspection

1. 1
   Turn the ignition switch to the OFF position.
2. 2
   Drain the ECTS (see Draining).
3. 3
   After immersing the sensor thermistor in engine coolant, measure the resistance between ECTS terminals 3 and 4.
4. 4
   Check that the resistance is within specification.

   Specification: Refer to "Specifications"

DEPOSIT

1. 1
   Turn the ignition switch to the OFF position and disconnect the negative (-) battery cable.
2. 2
   Disconnect the engine coolant temperature sensor connector (A).

   

3. 3
   Refill the engine coolant (Refer to Cooling System in EM group).

REMEDY

1. To install, reverse the removal procedure. Engine coolant temperature sensor: 29.4 ~ 39 N·m