CYLINDER GROUP 7J7974 - Caterpillar

electronic control module (ECM) is the computer which controls the engine. The flash file is the software which controls the behavior of the ECM.
Illustration 1 g00319343
ECM (typical example)
(1) Fuel outlet
(2) ECM
(3) Fuel inlet ECM (2) is cooled by fuel as the fuel circulates through a manifold inside the control module. The fuel from the fuel transfer pump enters the control module at fuel inlet (3). The fuel exits the control module at fuel outlet (1).
The flash file has all of the software and instructions for the ECM.
A control map defines the fuel rate, the timing, and other similar values. These values are defined for various operating conditions in order to achieve the optimum engine performance and fuel consumption. These values are programmed into the flash file.The ECM consists of the following items:
The ECM has a microprocessor that is used to perform computing functions. The microprocessor is necessary for the ECM to execute these functions:governing, injection timing control, system diagnostics and data link communications. The microprocessor receives instructions from the software in the flash file.
The ECM has a permanent memory that is used to store programmable parameters and diagnostic codes.
Input circuits filter electrical noise from the sensor signals. Input circuits protect the internal circuits of the ECM from potentially damaging voltage levels.
Output circuits provide the high currents that are necessary to energize the injector solenoids, the lamps, and the relays.
Power circuits provide high voltage for the injector solenoids. Power circuits provide clean stable electrical power for the internal circuits and for the external sensors.