audi a6 avant coding
 

I'm a very new owner of a 2007 A6 avant. I have been a mechanic all my life but I am new to audi's.I got my avant but it was water damaged so I purchased a salvage a6 for donor parts and all has gone very well but I have a gateway module improperly coded code that keeps cutting out my radio. I have a Autel Maxisys that will code modules but I cannot figure out which module is giving the code and how to code the replacement module. Any feedback would be much appreciated.