Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
If cause of "Drive train data bus defective" fault, for example, is not found in bus wires, check whether one of
the control units is responsible for the problem.
Test requirement:
• Vehicle diagnostic, testing and information system VAS 5051 connected up and vehicle self-diagnosis se‐
lected => Page 162
All control units using data bus for communication still disconnected; Ignition off
- Connect one of the control units.
-> Readout on VAS 5051:
- Switch on ignition.
- From list -1- select appropriate vehicle system.
- Interrogate and erase fault memory of control unit just connected.
- Touch ◂ key.
- From list -1- select diagnostic function "06 - End output".
- Switch ignition off and on again.
- Leave ignition switched on for 10 seconds. Then use fault reader to read out fault memory of control unit
just connected.
- If fault "Drive train data bus defective" is read out, replace control unit just connected.
- If fault "Drive train data bus defective" is not read out, connect next control unit and repeat sequence.
2 - Immobilizer self-diagnosis - immobilizer III
2.1 - Immobilizer self-diagnosis - immobilizer III
2.2 - General information
Note:
As from 02.99 the Audi A8 is fitted with immobilizer III. Immobilizer III is the successor to the existing immobilizer
II (variable code immobilizer).- The main difference to the previous immobilizer II is that the engine control unit
is actively incorporated into the evaluation and monitoring process. Also, the immobilizer control unit is now
integrated into the dash panel insert. The mechanical servicing of the immobilizer is identical to that for the
previous version, and is carried out as set out in the Workshop Manual.
Audi A8 1994 ➤
Electrical system Self-diagnosis 02.99 ➤ - Edition 05.2002
72 01 - Self-diagnosis
To Next Page
Loading...
