help a6 ecu fault code

[blknight05]

hi i have a 2.7 tdi a6 2007 avant i noticed the exhaust note keeps changing pitch up and down on tickover but the engine sounds ok,now the ecu managment light has come on,so iv scaned the ecu for fault codes and its come up with two 05504 and 04203 does anyone know what these mean? any help would be much apreciated thanks

[TheMatador]

Strange codes - they're not on the Ross-Tech site. What did you scan with?

[blknight05]

Yeh i think il have todo another scan