Self Study Program 287 – AUDI A8 2003 – Electrical Components

VAG SSP 287. This Self Study Programme contains information on data bus networking (topology) and electrical components in the Audi A8 2003. An understanding of the interaction of the components and distributed functions forms the necessary basis for successful fault-finding.

This introduction contains explanatory notes to clarify the meanings of certain terms, designations and symbols used in this Self Study Programme.

More detailed information can be found in the following Self Study Programmes:

Definition of terms

Data bus network (topology)

The topology provides a general outline of the way in which control units fitted in the vehicle are interlinked by way of data bus systems. It thus becomes clear which bus systems are used by the control units to exchange data.

Distributed functions

This term indicates that several control units are required to exchange information in order to implement a function.

Function master

With distributed functions, one control unit is always responsible for the entire sequence of operations. The function master control unit gathers all input information. The requests resulting from this are then transmitted in the form of a message on the data bus system and read into the control units concerned for corresponding actuation of the appropriate connected components.

Substitute master

In the event of function master failure affecting major functions, the task of the function master is assumed by a control unit provided for this purpose and designed to maintain the sequence of operations (possibly with certain restrictions).


Ignition switched on by way of electric ignition/starter switch or Advanced Key, so that entry and start authorisation control unit J518 transmits terminal 15 and 75x information to convenience CAN. The intermittent wiper switch E22 transmits the information “Wiper speed 1” to the steering column electronics control unit J527.

  1. The steering column electronics transmits the information “Wiper speed 1” to the  onboard power supply control unit J519.
  2.  The onboard power supply control unit transmits the information “Wiper speed 1” via the LIN to the wiper motor control unit J400.
  3. The wiper motor control unit actuates the integrated motor.


  • Introduction
  • Control Units
    • Drive system CAN/convenience CAN connectors
    • Data bus diagnostic interface J533 (gateway)
    • Energy management control unit J644
    • Control unit with display in dash panel insert J285
    • Convenience system central control unit J393
    • Boot lid control unit J605
    • Anti-theft/tilt system control unit J529
    • Onboard power supply control unit J519
    • Wiper motor control unit J400
    • Onboard power supply control unit 2 J520
    • Door control units J386 to J389
    • Sunroof electronics control unit J528
    • Garage door operation control unit J530
    • Entry and start authorisation control unit J518
    • Driver identification control unit J589

The Self Study Programme contains information on design features and functions.

The Self Study Programme is not intended as a Workshop Manual.
Values given are only intended to help explain the subject matter and relate to the software version applicable when the SSP was compiled.

Use should always be made of the latest technical publications when performing maintenance and repair work.

Language: English
Format: PDF
Pages: 96

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