The P0118 code means that the engine control module (ECM) has detected a voltage signal that’s too high from the engine coolant temperature (ECT) sensor (below). In practical terms, the ECM believes ...

Here's what drives cars of the '80sâ the Electronic Computer Module(ECM).Typical GM unit has an analog board to run sensors, digital board for"thinking" and memory. Removable PROM(at left)calibrates ...