Engine Coolant Temperature Sensor

The engine coolant temperature (ECT) sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

Fig 1: Engine Coolant Temperature (ECT) Sensor, Terminal And Gasket

Courtesy of NISSAN NORTH AMERICA, INC.

< Reference data >

Engine coolant temperature [°C (°F)]

Voltage⁽¹⁾ (V)

Resistance (kΩ)

-10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.35 - 2.73

50 (122)

2.2

0.68 - 1.00

90 (194)

0.9

0.236 - 0.260

⁽¹⁾	These data are reference values and are measured between ECM terminals.

Fig 2: Engine Coolant Temperature (ECT) Sensor Resistance Graph

Courtesy of NISSAN NORTH AMERICA, INC.