The first motor locks the door, the second motor blocks the remote control of the doors - the so-called safety function. After this, the doors cannot be opened from the inside.
The actuators on the fuel filler cap and tailgate consist of one motor and can be replaced separately.
After an accident with airbag deployment, the central door locking control unit unlocks the doors if they were locked. The control unit is located in front of the driver's seat, under the left carpet.
We do not describe here the process of dismantling individual parts of the system, but only show where these parts are located.
Details of the centralized door locking system: 1 - Control unit 3387 for front right door, 2 - Control unit 3389 for rear right door, 3 - Engine V155 for unlocking fuel filler flap, 4 - Engine V159 for unlocking rear door (trunk), 5 - Control unit J388 for rear left door, 6 - Control unit J386 for driver's door, 7 - Central control unit for convenience system (behind the first pillar trim, below), 8-pin switch for the hood.
[This article was copied from an online resource AUDIMANUAL]