I'm not in your area but have you considored purchasing a vw scan tool for yourself? Many are affordable and might help your diagnosis issue. There are many "vag" scanners on amazon ($20-$150+), obdeleven used with android devices (less then $100) and finally the windows compatible based usb cable/software combo, called vcds by ross tech ($199+: depending on which version/how many vin #'s you want to scan).
If you are willing to invest in a vw/vag scan tool; let us know your budget and we can discuss your specific options. Thanks.
Note: many repairs require the use of a vw type scan tool; you will save allot of money and enable you to do many repairs yourself and not be depedant on a vw dealer or pro shop to scan for trouble codes, fix things.
just bought this one for $35
'cause I could not find my old Android-connected unit. Quickly diagnosed the dreaded O2 sensor on another car (Ford). one data point, but it listed the code and "decoded" it to english
Another option is OBDEleven, which is under $100; runs on android and at this time with basic support on ios/apple devices. The company is based out of eastern europe, so support is not as good as others and it is a product, in somewhat if a "working beta", as they continue, to make updates, to the software, release the version 2 of the wireless dongle and work on full ios compatability. They have email support and forums but not at the pro level or maturity if the vcds product.
Aside from that, there are many different Chinese knockoff "VAG" handheld vw specific scan tools; cheap and plentiful, they can be clunky designed interface, have limited support (sometimes none and software updates may not exist or be sporatically be released) and many times almost no documentation. You get what you pay for; don't expect much support or ease of use, on the cheaper scan tools.