what's this code?

[RndLiteBMW at aol.com]

That's actually a pretty common code with VWAG products, mostly MkIII Jettas/Golfs... It has to do with the fuel trim at idle I believe, and when it says "limit reached" it's exceeded the parameters of the specified fuel trim adjustment "window" for that load range, and has had to move to another one.  There is procedure to actually alter the fuel trim adaptation with the VAG or AST tools to prevent this code from being a regular occurance. It's actually a Technical Service Bulletin in VW's case- not sure about Audi though.

Tucker Fritch
'83 UrQ
'86 4kcsq
'82 Vanagon
'68 2002