- do not disconnect the battery pack (AB) when the engine is running;
- before starting work on the fuel system, release the pressure in it. The pressure in the system drops on its own within a few hours after the engine is turned off;
- before checking the injection system, check the ignition system;
- the plug-in connections (PC) of the ECU-KSUD must be disconnected and connected only with the ignition off;
- monitor the completeness of the battery charge and the reliability of its connection;
- do not use battery chargers to start the engine;
- to quickly charge the battery, you need to remove it from the car;
- do not expose the ECU-KSUD to temperatures above +80°C;
- when measuring compression in cylinders, turn off the ECU-KSUD (DME).
The engine power supply system includes a number of systems, the main ones of which are:
- air supply system;
- fuel supply system;
- integrated Engine Management System;
- exhaust gas release (discharge) system.
(Information taken from this resource BMWman.ru)