Coolant Temperature (ECT) Sensor (Hyundai Elantra XD)

The coolant temperature sensor is installed in the cylinder head and monitors the coolant temperature and transmits a signal to the ECU. The sensor uses a thermistor, which is sensitive to temperature changes.

The electrical resistance of a thermistor decreases as the temperature increases. Based on the sensor output voltage, the ECU determines the engine temperature and ensures the optimal air-fuel ratio when the engine is cold.

Examination

1. Remove the sensor from the cylinder head.

2. By heating a vessel with water and a sensor located in it, check its resistance.

Coolant temperature sensor

Temperature	Resistance, kOhm
–20°C	14,13–16,83
0°C	5,79
20°C	2,31–2,59
40°C	1,48
60°C	0,586
80°C	0,322

Coolant temperature gauge

Temperature	Resistance, Ohm
60°C	125
85°C	42,6–54,2
110°C	22,1–26,2
125°C	15,2

3. If the sensor resistance differs from the required value, replace the sensor.

Installation

1. Apply THREEBOND TB 2403 or equivalent to the sensor threads.

2. Screw in the sensor and tighten it to the torque specified in the specification. Tightening torque: 20–40 Nm.

3. Connect the connector to the sensor.