Kia Optima DL3 Quiz
Engine Control System/Fuel System

Engine Coolant Temperature Sensor (ECTS)

In this manual: Engine Control System/Fuel System
General Information — 8Advanced Driver Assistance System (ADAS) — 21Maintenance — 27Engine Mechanical System — 45Engine Electrical System — 11Emission Control System — 11Engine Control System/Fuel System — 25Automatic Transmission — 20Drive Shaft and Axle — 7Suspension System — 22Steering — 7Restraints — 11Brake System — 22Body (Interior and Exterior) — 116Body Electrical System — 90Heating, Ventilation, and Air Conditioning — 32
11steps
~66min
3/5difficulty
02040608010039.229N·mlb·ft
Tightening torque found on this page
Done 0 of 11

Specifications

Specification

Temperature Resistance (kOhm)
°C °F
45 113 244,8 - 281,4
55 131 162,5 - 186,5
60 140 133,5 - 153,5
71 159,8 88,93 - 102,13
85 185 55,16 - 63,36
110 230 26.02 - 29.82
125 257 17,5 - 19,7

Description and Operation

Description

  • The Engine Coolant Temperature Sensor (ECTS) is installed in the engine coolant passage of the cylinder head to detect the 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 reference +5V 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 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 based on the engine coolant temperature information to prevent engine stalling and improve drivability.

Components and Component Location

Component Location

1. Engine Coolant Temperature Sensor (ECTS)

Circuit Diagrams

Wiring Diagram

Harness Connector

Repair Procedures

Inspection

  1. The engine control system can be diagnosed more quickly for malfunctions using the Kia Diagnostic System (KDS). (Refer to Diagnostic Trouble Code Guide)

    KDS provides the following information.

    1. Self-diagnosis: Checks and displays diagnostic trouble codes (DTC).

    2. Data list: Checks the input/output values of the system.

    3. Active test: Checks the operating condition of the system.

    4. Additional functions: System option control, zero point adjustment, and other functions.

Component Inspection

  1. Turn the ignition off.

  2. Disconnect the engine coolant temperature sensor connector.

  3. Remove the sensor.

  4. After immersing the sensor thermistor in engine coolant, measure the resistance between the ECTS signal terminal and the ground terminal.

  5. Make sure the resistance is within specification.

    Temperature Resistance (kOhm)
    °C °F
    45 113 244,8 - 281,4
    55 131 162,5 - 186,5
    60 140 133,5 - 153,5
    71 159,8 88,93 - 102,13
    85 185 55,16 - 63,36
    110 230 26.02 - 29.82
    125 257 17,5 - 19,7

Removal

  1. Disconnect the negative battery cable.

  2. Remove the battery.

    (Refer to Engine Electrical System - Battery)

  3. Disconnect the engine coolant temperature sensor connector (A).

  4. Remove the ECTS (A).

    Tightening torque: 29.4–39 N·m

Installation

  1. Install in the reverse order of removal.

  2. Fill the engine cooling system with coolant.

    (Refer to Engine Mechanical System - Engine Coolant)

Test yourself

A quick Kia Optima DL3 quiz: every answer comes with an explanation and a link to the manual page.