Engine Coolant Temperature Sensor

WARNING: This page is about a different car, the 2012 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

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.