When the ground wire is removed from the battery, the memory of the electronic control units and radio receiver is erased.
The standard equipment of the car includes a radio receiver with a coded anti-theft device, which is based on a microprocessor. After disconnecting the radio receiver from the vehicle's on-board network (removing the battery, radio or initial installation of the radio) you must enter a security code. The radio can only be turned on after entering the correct code.
Before removing the ground cable from the battery, check whether you have the radio code. Without the security code, the radio can only be put into operation at a specialist Audi service station.
The individual security code for the radio receiver is contained in the technical documentation included with the vehicle upon sale.
Fig. 18–63. Special key 3344 for removing the radio from the car
To remove the radio receiver, you must use two special keys 3344 (Fig. 18–63).
Insert the two keys into the narrow slots located on both sides of the radio until the keys are locked. The inscriptions on the keys should be located at the top. The key with the inscription "Top L" should be installed on the left side, and the key with the inscription "Top R" - on the right side of the radio.
Fig. 18–64. Using special keys to remove the radio from the socket in the instrument panel
Using the key heads, remove the radio from the socket (Fig. 18–64), being careful not to tilt it or pull it to the side.
Disconnect the speaker and antenna electrical connectors from the radio, as well as the multi-pin connector that supplies power to the radio. If non-multi-pin connectors are used for the connections, label the connectors before disconnecting them.
Installation
Remove the special ones keys from the radio.
Connect the electrical connectors to the back of the radio.
Insert the radio into the instrument panel socket until the spring clips snap into place.
Connect the ground wire to the battery.
After installing the radio, enter the security code.
Text provided by the online resource AudiManual