Hyundai Sonata LF: 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 that changes resistance
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.
Connect a GDS on the Data Link Connector (DLC).
2.
Measure the output voltage of the BPS at idle and IG ON.
Specification: Refer to "Specification"
Removal
1...
Other information:
Specifications
Smart Key Unit
ItemsSpecificationRated voltageDC 12VOperating voltageDC 9 ~ 16VOperating temperature-22°F ~ 176°F (-30°C ~ 80°C)LoadMax. 4mA (When welcome light function off)
RF Receiver
ItemsSpecificationFrequency433.92 MhzAntenna typeFSK (Frequency Shift Keying)
Smart Key Fob
ItemsSpecificationBatteryLithium battery 3V 1EADistance30m from vehicle, RF : 30m, Passive(LF) : 0...
Description
BSD is a system that uses two magnetic wave radar sensors
attached on the rear panel to measure the distance from the following
vehicles and provides the sensing and (visual and auditory) alarm of any
vehicle coming into the blind spot...