Engine Coolant Temperature Sensor (ECTS)

Specifications

Specification

▷ Type: Thermistor Type

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

Description and Operation

Description

Located in the engine coolant passage of the cylinder head. The Engine Coolant Temperature Sensor (ECTS) detects the engine coolant temperature. The ECTS uses a thermistor whose electrical resistance changes with temperature. The electrical resistance of the ECTS decreases as the temperature rises, and increases as the temperature drops. A 5 V reference voltage is supplied to the ECTS through a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the ECTS are connected in series. As the thermistor resistance in the ECTS changes with the engine coolant temperature, the output voltage also changes. During a cold engine start, the ECM increases the fuel injection time and adjusts the ignition timing according to the engine coolant temperature to prevent engine stall and improve drivability.

Circuit Diagrams

Wiring Diagram

[A/T]

[M/T]

Repair Procedures

Inspection

1. 1
   Turn the ignition off.
2. 2
   Remove the ECTS. (Refer to Removal)
3. 3
   After submerging the sensor thermistor in the engine coolant, measure the resistance between terminals 3 and 4 of the ECTS.
4. 4
   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
   Remove the air cleaner. (Refer to Engine Mechanical System - "Air Cleaner")
3. 3
   Remove the battery. (Refer to Engine Electrical System - "Battery")
4. 4
   Disconnect the engine coolant temperature sensor connector (A).
5. 5
   Remove the Engine Coolant Temperature (ECT) sensor (B). Engine Coolant Temperature Sensor: 29.4–39 N·m

   

Installation

1. 1
   Install in the reverse order of removal.
2. 2
   Refill the engine coolant. (Refer to Engine Mechanical System - "Coolant").