Component Description

NOTE: If DTC P0125 is displayed with P0117, P0118, first perform trouble diagnosis for "DTC P0117, P0118 ECT SENSOR ".

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.

Reference data

Fig 2: ECT Sensor Temperature Versus Resistance Graph

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

ECT SENSOR RESISTANCE/VOLTAGE SPECIFICATIONS

Engine coolant temperature °C (°F)

Voltage⁽¹⁾V

Resistance kΩ

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⁾	These data are reference values and are measured between ECM terminal 73 (Engine coolant temperature sensor) and ground.

CAUTION: Do not use ECM ground terminals when measuring input/output voltage. Doing so may damage the ECM's transistor. Use ground other than ECM, such as body ground.