12 00 Contents of Engine Electrical System General

Safety instructions: Always switch off ignition before working on ignition system. Use only test leads which have been approved and belong to the testing instruments (e.g. DIS Tester). Comply with operating instructions of the respective testing instrument used. Comply with the country-specific safety regulations. Never touch components conducting current with engine running! Comply with instructions of DIS tester. Do not connect any suppression capacitors or inspection lamps to terminal 1 on the ignition coil. Terminal 1 of ignition coil must not be connected to ground or battery positive lead. If an alarm system is subsequently installed, lead of terminal 1 must not be used for start prevention. When working on ignition system, always disconnect supply leads to ignition coils. High voltage at: Ignition lead - Spark-plug connector - Spark plug - Ignition coil (high voltage at terminal 4 is approx. 40 kV) - Lead of terminal 1 from ignition coil to DME control unit (high voltage approx. 350 V).

General Information -> Working on ignition system. Refer to 12 00 ... INFORMATION ON WORKING ON IGNITION SYSTEM.

1. -> Removing and installing electronic control units. Refer to 12 00 ... INSTRUCTIONS FOR REMOVING AND INSTALLING ELECTRONIC CONTROL UNITS .
2. -> Welding work (overload protection of control units). Refer to 12 00 ... INSTRUCTIONS FOR WELDING WORK (OVERLOAD PROTECTION OF CONTROL UNITS) .
3. -> Disconnecting and connecting battery. Refer to 12 00 INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY  .
4. -> Disconnecting and connecting test equipment. Refer to 12 00 ... INSTRUCTIONS FOR CONNECTING AND DISCONNECTING TEST UNITS .
5. -> Component inspection: Refer to 12 00 ... INSTRUCTIONS ON COMPONENT TESTING .
6. -> External jump-starting aid. Refer to 12 00 ... INSTRUCTIONS ON STARTING AID .