Radio coding A3, 2.0 TDI S-Line 2007.

I ran a scan on my Wife's car, as above last night, expecting a problem in the Heater/air-con but just got codes for the Radio which as far as we are aware works fine. I don't have the scan to hand but one says radio incorrectly coded, one seems to suggest it's looking for an autochanger which doesn't exist and one suggests it's looking for a mobile phone connection which it's never had.
Is it possible these have carried over from teh previous owner, maybe the radio has been changed at some time and the coding not done properly. I am not aware of it ever having an auto changer but I suippose it's possible, doesn't have it now anyway. It probably has had a carphone but not any more. Thinking maybe there is a coding for the radio which needs changed but have no idea how to do this or where would I get the code from. The last 2 I suppose may be fixed by the first but otherwise maybe need autochanger and carphone disabled?
None of this any help towards finding out why exhaust fumes are coming in through the heater, investegations still ongoing for this and before anyone says it, NO it doesn't have an exhaust leak.
Any advise info appreciated.
Cheers

Anyone any ideas?

Good point, have to admint there must be a leak but I can't find it. As far as the exhaust system it's self is concerned I have semi-blocked the tailpipes to increase pressure and covered it section by section with Cif bathroom mousse then got someone to start the car, this should show up any leak but nothing. Got as far up as the front flexi. From under the wheelarch with the wheel and inner platic cover removed I can see the DPF, all one side and the top and it all looks fine. Under teh bonnet has a good seal and it mates with teh bonnet when shut, I have the undertray off the car so plenty draft and less likelyhood of blowing past the seal to teh heater intakes but it still comes in. Visual inspection of everything under the bonnet; nothing. Next I plan to remove the air box and intake so I can see teh EGR pipes and other side of the DPF, after that, maybe the air vents behind the rear bumper but against this is I am sure it comes through the heater.
Thanks for the Radio advice, I am happy to live with teh code but one thing is I get regulay electronicy mobile phone noises throught the speakers which I am thinking may be because the mobile phone side is enabled, so I would like to switchthisoff is possible. We have another A3 and it has none of these problems so it must be possible to fix them or that's what I keep telling myself.