A3 TDI LIMP HOME BOOST ERROR??!

[Jconway651]

Looking for a bit of help....

I have (my girlfriend drives) an A3 2.0 TDI 170PS (6 speed) 2009

The glow plug symbol keeps coming on and the car is going into limp home mode.
Ran a VCDS scan on it and im getting this code..

000665 - Boost pressure recirculation
P0299 - 000 - Control Range Not reached - MIL ON
RPM : 2668 /min
Speed: 90,0 km/h
Load: 100.0 %

I took the EGR off and cleaned it. It was full of crud so id assumed it was that.
However reading on internet has suggested it cound be:
N75 valve.
Vac leak.
Diverter Valve (do TDI's have this ??)
Or could it still be the EGR??

EGR is £230 from audi so hoping its something simple... Any help appreciated. Just hoping its something common and cheap.