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:
Description
The PTC (Positive Temperature Coefficient) heater is installed at the exit or
the backside of heater core.
The PTC heater is an electric heater using a PTC element as an auxiliary heating
device that supplements deficiency of interior heat source in highly effective
diesel engine.
Inspection
1.
Disconnect the negative (-) battery terminal.
2.
Remove the front door trim.
(Refer to Body - "Front door trim")
3.
Disconnect the power door mirror connector from the harness
4.