Circuit Description
WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. If the ECM detects a high ECT signal voltage, which is a low temperature indication, this DTC sets.
The following table illustrates the difference between temperature, resistance and voltage:
DTC P0118
| ECT | ECT Resistance | ECT Signal Voltage |
|---|---|---|
| Cold | High | High |
| Warm | Low | Low |