Can you get the car scanned (VCDS)?
There is a fault there (obviously), but insufficient information at this time for anyone to give any assistance.
To help everyone here, please indicate in your profile
1) Where you are from
2) What model Touareg you have (I know you mentioned it in your post - but so much easier if you declare this in your profile).
Maybe, once we know where you reside, more detailed assistance, suggestions re VCDS scanning can be offered.