So I have been looking at a 2008 A6 Avant Quattro 3.2 with 130K miles and had a PPI done on it by an independent German shop. Aside from a few mechanical things easily addressed
( bushings, vacuum pump ), the shop reported a series of repeated codes, as follows:

009523 Ign. switch
01826 Steering angle
00929 Central locking
61 Battery reg.
01964 Control head

I reported this to the selling used car dealer, who later reported back that they replaced the battery and registered it, which cleared all the codes. As a newbie civilian I have no idea if this truth or baloney. Does that sound plausible?

The last issue is that evidently it has an intermittent problem with the HVAC motor working, but no air in the cabin. When I test drove it it did not show up, but the examining shop had seen this car before and noted it as an issue under the previous owner. Expensive to fix?