Yeah, however on newer Ross-Tech VAG COM’s and all dealer’s readers now, they’ve been able to bypass that problem even when the k-line is hooked up wrong. I remember having to show pictures of my stereo wiring to dealers, and assure them I knew about the k-line and bypassed it correctly, or else they wouldn’t hook my car up to their stuff. There was a time that an aftermarket radio, hooked up to the K-Line incorrectly, would blow out the dealer’s reader.
The problem with Audi’s was that the aftermarket harness adapters didn’t hook the wiring up correctly. If the person installing knew about the k-line, though, they could just splice around that or reconfigure the harness.
Hope that’s it here, though, as that’s a simple fix.