well 1st thing is to make sure your car is under lock & key at dealership ready to have the locks changed immediately, I wouldnt leave my car anywhere else mate even if I had another key to lock/unlock/start car, what a typical stupid thing for stealership to say, they should have arranged collection straight away so you dont lose the car.
When you say plastic key fob do you mean the clear plastic tag with numbers on? In which case, yes you can start the car if you have the Security Key Code (or at least you could on many of the more recent cars).
The dealership can also de-register a key from the immobilisor - or so could you if you have another key and VCDS.
So I'm assuming its a keyless & go car then, so hows the security code entered, via the MMI interface? Cause I always knew the clear plastic tab as the key number not any security code.
Also the keyless fob has the emergency key in top of the fob no?? So even if they deactivated it can still be accessed, just curiosity more than anything else.
Didnt think VCDS could disable the immobiliser in the key without other security access can it Stu just the locking side, as its new system on these its all through germany or if you have key pro with proper kit
I don't really know much about the Keyless Entry systems however the process of learning new keys to the Immo would be much the same I would think and so you'd simply 'delete' any key pairings and then re-learn the new and any remaining keys.