Gas Cap Light

I don't know about a "gascap light" so I assume you mean "check engine light." The check engine light indicates that the computer has detected a malfunction in the engine/emission control system and has diagnostic codes and data stored which would be essential in diagnosing the problem. A technician with a scanner can access the diagnostic codes and data and then be able to give you a diagnosis. If you want to find an Audi specialist, here's our directory link for you: https://repairpal.com/audi-repair-in-houston-texas