Adding the alarm chirp for arm and disarm as well as altering the operation of the warning lights is possible via Vagcom/VCDS. This only works on cars with the factory alarm which is standard on all GTI’s, R32’s, some Passat and Jetta models and optional on models like the GT Sport TSi/TDI. USA specification don’t have the battery backed up siren but have a car horn fitted instead, there are how to guides on vwvortex.com on upgrading this horn to the siren that the rest of the world receive.
Step 1. Using Vagcom/VCDS open controller 46 – Central Convienence and click on Coding.
Step 2. Unlocking confirmation, adjust the approriate settings.
Step 3. Locking confirmation, adjust the approriate settings.
Step 4. Bit 4 turns the siren on/off, Bit 5 is the type of siren tone, Bit 6 the siren alarm type and Bit 7 allows changes in the MFD.