Try this:
Purpose: to set confirmation of door locking/unlocking with beep (alarm) or horn. Attention! There are 5 lines of coding here, see 6. (After coding, activate the option on your screen if it doesn’t work, in CAR – Open/Close settings – check Acoustic Confirmation) Proceed : 1 – Engine off...
www.vag-coding.net
I did it with OBDELEVEN and it worked, but then I had to remove it, because I do not have the alarm horn and using the main horn was * too loud* !
If anyone knows how to add an alarm horn (without actually installing the alarm) I would appreciate it.