P0125 ECT Sensor: Description

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 Component

< Reference data >

REFERENCE DATA

Engine coolant temperature °C (°F)

Voltage⁽¹⁾ V

Resistance kΩ

-10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.37 - 2.63

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 46 (Engine coolant temperature sensor) and 52 (Sensor ground).

Fig 2: Resistance And Temperature Graph