He tried reinstalling the VCDS software. Nothing. He tried different USB ports. Still dead. The car was running rough, and his weekend repair plan was slipping away.
So if you ever see in your downloads folder, don’t ignore it. It might be the exact key your interface needs — not the newest, but the right one. vcds usb driver version 02.10.00
He reopened VCDS. Green check mark. USB connected. K1, K2, CAN: OK. He tried reinstalling the VCDS software