Engine Control Module: Notes

The Engine Control Module (ECM), located under instrument panel on passenger side, is control center of fuel injection system. See Fig 1 . It constantly monitors information from various sensors, and controls systems that affect vehicle performance. For service, ECM has two parts: Controller (ECM without MEM-CAL) and Memory-Calibration unit (MEM-CAL).

Fig 1: Electronic Control Module (ECM)

Courtesy of GENERAL MOTORS CORP.

The ECM looks at voltages from several sensors to determine how much fuel to give engine. The fuel is delivered under one of several conditions, called "modes". All modes are controlled by ECM, and are described below.