Audi Workshop Service and Repair Manuals > A3 Mk1 > Power unit | Motronic injection and ignition system (4-cylinder turbo) | Mixture preparation system, electronic inj.,Gas | Servicing Motronic injection system | Removing and installing engine control unit with and without protective housing | Replacement procedure for engine control unit without protective housing

Replacement procedure for engine control unit without protective housing

–	Connect up the vehicle diagnostic and service information system -VAS 5052- and select vehicle system “01 - Engine electronics”. The ignition must be switched on when doing so.

The vehicle diagnostic and service information system -VAS 5052- displays the control unit identification and the code -2-.

–	Always start by displaying and printing out the control unit identification.

–	Switch off ignition.

–	Unscrew the wiper arms.

–	Detach the plenum chamber cover and set it down towards the windscreen.

Note

Always switch off the ignition before unplugging or plugging in the control unit connectors.

–	Release the connector catches and unplug the control unit connectors.

–	Use a screwdriver to press aside the retainer tab of the mount and pull out the engine control unit to the front.

Installing

Install in reverse order, paying attention to the following:

–	Bend back the retainer tab of the mount.

The following operations must be performed after connecting the new engine control unit:

–	Code engine control unit → Chapter.

–	Perform adaption of throttle valve module -J338- → Chapter.

–	Perform adaption of kick-down function for vehicles with automatic gearbox → Chapter.

–	The immobilizer must be enabled using vehicle diagnostic and service information system -VAS 5052-.

–	In “Guided Fault Finding” mode, “Select type” menu, select the option “Remaining vehicles for online immobiliser interface” and follow the instructions in Guided Fault Finding.