Component Description

WARNING: This page is about a different car, the 2010 Infiniti M45. However, it is still accessible from the selected car via links, so may be relevant.

The engine coolant temperature 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: Identifying ECT Sensor

Courtesy of NISSAN MOTOR CO., U.S.A.

VOLTAGE AND RESISTANCE REFERENCE CHART

Engine coolant temperature [°C (°F)]

Voltage⁽¹⁾ (V)

Resistance (kΩ)

-10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.1 - 2.9

50 (122)

2.2

0.68 - 1.00

90 (194)

0.9

0.236 - 0.260

⁽¹⁾	This data is reference value and is measured between ECM terminal 73 (Engine coolant temperature sensor) and ground.

Fig 2: Resistance And Temperature Graph

Courtesy of NISSAN MOTOR CO., U.S.A.

CAUTION: Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.