DTC P0117: Engine Coolant Temperature Sensor Circuit Low Input & DTC P0118: Engine Coolant Temperature Sensor Circuit High Input: Description

The engine coolant temperature sensor is used to detect the engine coolant temperature. The sensor 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. See Fig 1.

Fig 1: Engine Coolant Temperature Sensor Identification & Reference Data

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