I am trying to sell my 06 A6 and my check engine light came on. Took it to a certified mechanic and they said don’t worry about it it’s nothing serious maybe a sensor. I then took it to an Audi dealer and they said a evaporation sensor possibly then twisted the fuel cap and it turned off . My question is, is this a easy inexpensive fix?
A loose or faulty gas cap is often the problem for an evaporative system-related CEL. If it doesn’t come back on you’re lucky. If it does, the next thing I’d do is replace the cap with a new one from Audi.
If the genuine Audi cap doesn’t fix the problem, you should get this repaired and diagnosed
Somebody will have to retrieve the fault codes, diagnose the problem, perform the repair and verify that the repair was successful.
After all that, it would be a good idea to get the car smogged. That would make your car more attractive to prospective buyers.