Here's the code on the VAG-Com Wiki:

http://wiki.ross-tech.com/wiki/index.php/17963/P1555/005461

But it sounds like it's over boosting which can't be alright as its throwing a code, I'm not sure of the full implications of over boost to be honest, but it doesn't sound good

I'll take my chances tbh,it runs fine & returns good mpg.It doesn't get driven hard at all either,the Mrs uses it most.

I just think looking at all the things it could be,it seems like a lot of time & hassle to probably still be none the wiser & end up with that code still remaining.

I googled the error code & someone on an Audi forum had it,they changed the turbo,the n75 and other stuff & still got the code.

I'm not going down that road

as an update to this,

I've been checking for codes since the last post a few weeks back & 500 odd miles on,the code has not reappeared.

R-tech did say it usually came up only in cold weather.

So all's well