Hyundai Venue (QX): Engine Control System / Engine Coolant Temperature Sensor (ECTS). Description and operation
Engine Coolant Temperature Sensor (ECTS) is located in the engine coolant passage
of the cylinder head for detecting the engine coolant temperature. The ECTS
uses a thermistor whose resistance changes with the temperature.
The electrical resistance of the ECTS decreases as the temperature increases,
and increases as the temperature decreases. The reference +5V is supplied to
the ECTS via a resistor in the ECM. That is, the resistor in the ECM and the
thermistor in the ECTS are connected in series. When the resistance value of
the thermistor in the ECTS changes according to the engine coolant temperature,
the output voltage also changes.
During cold engine operation, the ECM increases the fuel injection duration
and controls the ignition timing using the information of engine coolant temperature
to avoid engine stalling and improve drivability.

Inspection
1.
Turn ignition switch OFF.
2.
Disconnect IATS connector.
3.
Measure resistance between IATS terminals 3 and 4.
Specification
Temperature [°C (°F)]
Resistance (kΩ)
-40 (-40)
48.14
-20 (-4)
14.
Other information:
Refrigerant System Service
Basics (R-134a)
Refrigerant Recovery
Use only service equipment that is U.L-listed and is certified to meet the requirements
of SAE J2210 to remove HFC-134a(R-134a) from the air conditioning system.
Inspection
•
Before measuring the pressure of the refriferant line, check
whether the refrigerant amount is charged in accordance with
the specified charging amount.