DTC P0116: Engine Coolant Temperature (ECT) Sensor 1 Circuit Range/ Performance Problem: General Description

The powertrain control module (PCM) supplies voltage to the engine coolant temperature (ECT) signal circuit (about 5 V) through a pull-up resistor. As the engine coolant cools, ECT sensor 1 resistance increases, and the PCM detects a high signal voltage. As the engine coolant warms, ECT sensor 1 resistance decreases, and the PCM detects a low signal voltage. If the ECT sensor 1 output voltage does not reach a set temperature after starting the engine and driving a set time, or when the difference between the ECT sensor 1 output voltage while driving and the output voltage of the ECT sensor 1 after the engine has been stopped a certain length of time does not change a certain amount, the PCM detects a malfunction and a DTC is stored.