Engine Control Module (ECM) Description and Operation: Notes

The ECM on this vehicle is also called an engine control module and is used in electric, hybrid, and conventional vehicle applications. The ECM interacts with many related components and systems, and monitors them for deterioration. Diagnostics monitor the system performance and a diagnostic trouble code (DTC) sets if the system performance degrades. The ECM is part of a network and communicates with various other vehicle control modules.

Malfunction indicator lamp (MIL) operation and DTC storage are dictated by the DTC type. A DTC is ranked as a Type A, B, or C DTC. Refer to Powertrain Diagnostic Trouble Code (DTC) Type Definitions . Other system control modules may request the ECM to illuminate the MIL. In these cases there is no fault with the ECM, and a DTC will set in the ECM indicating which control module requested the MIL illumination.

The ECM is the control center of the some of the vehicle control systems. Review the components and wiring diagrams in order to determine which systems are controlled by the ECM.

The ECM constantly monitors the information from various sensors and other inputs, and controls the systems that affect vehicle performance. The ECM also performs diagnostic tests on various parts of the system and may illuminate the MIL when it detects a malfunction that affects vehicle performance. When the ECM detects a malfunction, the ECM stores a DTC. The condition area is identified by the particular DTC that is set. This aids the technician in making repairs.