Hello all! Love the forum.. Just figured I have so many issues I might as well register
Today I decided I'll get my emission test done (2000 audi a6) I went for a joyride to warm it up and all that and once I figured I drove enough I went to get test done. They said they can't do the test because the cars computer doesn't communicate with.. Whatever device they use to do the emission (sorry as you can see my terminology is not all that great )

Does anyone know what the issue might be? They offered to do a diagnosis for $100 but I figured my mechanic would prob do a diagnosis for free so I left.. Has this happened to anyone? How easy/difficult is it to fix the issue?