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Component Description

CAUTION: Do not 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.
NOTE: If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or P0118. Refer to 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.

Reference data 

For identification of engine COOLANT temperature sensor components, see Figure .

For engine COOLANT temperature sensor specifications, see Figure .

For thermistor specifications in graph format, see Figure .