Audi Workshop Service and Repair Manuals

Notes:

• ◆ Test box V.A.G 1598/31 is designed so that it can be connected to the wiring harness for the engine control unit and to the engine control unit itself at the same time.
• ◆ This has the advantage of enabling the engine management system to remain fully operational even with the test box connected (for example, when testing signals while the engine is running).
• ◆ The instructions for performing the individual tests indicate whether or not the engine control unit itself also needs to be connected to the test box.

The following procedure is for engine control units without protective metal housing. For the procedure for engine control units with metal housing .

Removing engine control unit

• ‒ Switch off ignition.
• ‒ → Pull off rubber seal -1- from plenum chamber to the front.
• ‒ Remove plenum chamber cover.
• ‒ Remove both windscreen wiper arms -2- (mark positions before removal).
• ‒ Unclip scuttle panel trim (see arrows).

• ‒ → Remove control unit housing cover.

• ‒ → Carefully lever off the retainer bar with a screwdriver -arrow-.

• ‒ → Release retainer catch -arrows- and unplug connectors -1- and -2- from control unit.
• ‒ Take out engine control unit.

• ‒ → Connect test box V.A.G 1598/31 to wiring harness connector. Also connect earth clamp on test box to battery negative terminal. The instructions for performing the individual tests indicate whether or not the engine control unit itself also needs to be connected to the test box.
• ‒ Carry out test as described in the repair instructions.

Perform the following operations after reconnecting engine control unit:

• ‒ Interrogate fault memory and erase if necessary.

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