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 output voltage after driving a set time after starting the engine does not reach a set temperature, or when the difference between the ECT output voltage when driving and the output voltage of the ECT after the engine is stopped a set time does not change a certain amount, the PCM detects a malfunction and a DTC is stored.