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Replacing engine control unit > < Removing and installing intake-manifold changeover system components Engine code letters: ASN, BBJ

A4 Cabriolet Mk2

Motronic injection and ignition system (6-cyl.)
Servicing Motronic injection system
Wiring and component check using test box V.A.G 1598/31

Note:

Unplugging connectors from engine control unit erases learned values, however content of fault memory is retained.

Notes:
 
W00-0943
  • ◆ The test box V.A.G 1598/31 is designed for simultaneous connection to the engine control unit wiring harness and the actual engine control unit.
  • ◆ This has the advantage that the electronic engine management system remains fully operational with the test box connected (e.g. measurement of signals with engine running).
  • ◆ Whether or not the engine control unit is additionally to be connected to the test box is indicated in the appropriate test sequences.
  • ‒ Switch off ignition.
  • ‒ Remove engine control unit .

Note:

If engine control unit is provided with a sheet-metal housing (to prevent theft), housing must be separated from engine control unit for connection of test box. Procedure => Page 24-40. On completion of repair work, sheet-metal housing is to be re-fitted to engine control unit.
 
N23-0271
  • ‒ → Connect test box V.A.G 1598/31 to wiring harness connectors. Connect earth clip of test box to earth (not shown in Fig.). Whether or not the engine control unit is additionally to be connected to the test box is indicated in the appropriate test sequences.
Attention:
So as not to destroy electronic components, select required measuring range before connecting test leads and observe test conditions.

The following steps must be performed after re-connecting engine control unit:

  • ‒ Activate engine control unit in "Assisted fault-finding" under diagnosis item "Replacing engine control unit".

Use is to be made for this purpose of vehicle diagnostic, testing and information system VAS 5051.

Replacing engine control unit > < Removing and installing intake-manifold changeover system components Engine code letters: ASN, BBJ