Engine Coolant Temperature Sensor (ECTS)

Specifications

SPECIFICATIONS

▶ Type: Thermistor type

Description and Operation

Description

The engine coolant temperature sensor (ECTS) is located in the coolant passage of the cylinder head and is used to detect coolant temperature. The thermistor resistance in the ECTS depends on temperature.

The electrical resistance of the ECTS decreases as temperature rises and increases as temperature falls. A 5 V reference voltage is supplied from the ECM through a resistor to the ECTS. The resistor in the ECM and the thermistor in the ECTS are connected in series. If the thermistor resistance in the ECTS changes with coolant temperature, the output voltage also changes.

During a cold engine start, the ECM increases fuel injection duration and adjusts ignition timing according to coolant temperature so that the engine does not stall and drivability is improved.

Schematic diagrams

Circuit diagram

repair procedures

TEST

1. 1

   Turn the ignition off.

2. 2

   Remove the ECTS.

   (Refer to "Removal")

3. 3

   After immersing the thermistor of the sensor in coolant, measure the resistance between ECTS terminals 3 and 4.

4. 4

   Make sure the resistance is within 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	80	0,32
   100	212	0,19
   110	230	0,145~0,149
   120	248	0,12

expansion

1. 1

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

2. 2

   Remove the air filter.

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

3. 3

   Remove the battery.

   (Refer to Group EE — Battery)

4. 4

   Disconnect the engine coolant temperature sensor connector (A).

5. 5

   Remove the engine coolant temperature sensor (B).

   Engine coolant temperature sensor: 29.4~39 N·m

   

Installation

1. 1

   Installation is the reverse of removal.

2. 2

   Refill the coolant.

   (Refer to Engine Mechanical – "Coolant")