First, the OP needs to research the terms of the Lemon Law in his/her state. They do vary somewhat.
Second, the OP needs to have documentation of each visit to the dealership, with the complaint listed on each repair invoice.
Third, the OP needs to begin correspondence (via certified mail) with VW of America, regarding this problem. Contact info can be found in the Owner’s Manual. By quoting the exact wording of his/her state’s Lemon Law when corresponding with VW, the OP can make it very clear that the he/she know his/her rights in connection with that statute.
I drafted a letter for a friend who was having drivability problems with his Toyota Rav-4, and because I made it clear (by utilizing exact legalese from the relevant statute) in my letter that a Lemon Law complaint would be filed if there was one more failed repair attempt, I was able to get Toyota of America to react appropriately and rapidly. I even stated that the complainant would be demanding a full refund, rather than a replacement vehicle, as that course of action is far more costly for the mfr, and they want to avoid that at all costs. (Note: If you live in a “red state”, your legal rights may not be as broad as they are in my state.)
The third (and final) repair attempt was jointly carried out by Toyota’s regional service rep and a Japanese engineer (who barely spoke English). After a few hours, they were able to rectify the problem, and the service rep was very candid in telling us about the failures of the mechanics at the dealership when they (supposedly) attempted to repair the problem.
So…this problem needs to be kicked up to the next level.
Only the manufacturer/importer can act to replace your vehicle or provide a full refund under the Lemon Law, as the dealership is out of the loop in this regard. The sooner that you involve the manufacturer/importer, the closer you are to a resolution of the problem–whether that includes a repair, or a new vehicle, or a refund.