Kia Optima Hybrid Owner's Manual Quiz
Engine Control System/Fuel System

Engine Coolant Temperature (ECT) Sensor Description and Operation

In this manual: Engine Control System/Fuel System
General Information — 4Engine Mechanical System — 50Engine Electrical System — 20Emission Control System — 30Engine Control System/Fuel System — 84Automatic Transmission — 98Drive Shaft and Axle — 15Suspension System — 36Steering — 12Restraints — 50Brake System — 38Body (Interior and Exterior) — 54Body Electrical System — 233Heating, Ventilation, and Air Conditioning — 57
~1min read

Description

The Engine Coolant Temperature Sensor (ECTS) is installed in the engine coolant passage through 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 the temperature increases, and increases as the temperature decreases. A +5 V reference 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. 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 adjusts the ignition timing using the engine coolant temperature information to prevent engine stalling and improve drivability.

Test yourself

A quick Kia Optima Hybrid Owner's Manual quiz: every answer comes with an explanation and a link to the manual page.