DTC P0116: ECT Sensor Performance: Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 Saturn SW2, 2001 Saturn SL2, 2001 Saturn SL1, 2001 Saturn SL, and 2001 Saturn SC2. However, it is still accessible from the selected car via links, so may be relevant.
Engine Coolant Temperature (ECT) sensor is a thermistor that varies resistance according to changes in engine coolant temperature. ECT sensor resistance is high when coolant temperature is low. Resistance drops when coolant temperature increases. PCM provides a 5-volt reference and a ground to ECT sensor. During cold start, ECT and IAT readings are compared. DTC sets after PCM verifies proper operation of IAT sensor and difference between ECT and IAT reading does not fall within an acceptable range.