2005 (55) a6 avant key symbol

[a3_18t]

Hi guys n gals.
I'm looking at buying an a6 avant 2.0 diesel. It my bosses ex company car so been offered it for a bargain price. Problem is when you turn on the ignition a key symbol appears on the dash with 3 bleeps. The car drives fine I used it for the back holiday weekend and it never skipped a beat covered nearly 400 miles.
So what could this issue be and will it be expensive to fix?
Don't want to commit to buy it if it's going to cost me a grand to fix.
I have attached a pic of the message I get.
Any help much appreciated.

 

[c4a5er]

this, for an A4, the explanation down the page suggests it could be a defective ignition lock.....AFAIK any warning in red needs immediate attention..

http://www.audihelp.com/auda-13-auto_check_control.html

 

[D5URU]

Yes. it can be ignition lock, luckily in a6 4f it is simple swap, you don't need to change keys as it will accept "old" keys. Used ones available on ebay for faction of dealer price, just make sure to match part number with yours or get newer revision. A bit of work with removing and fitting, but nothing to scary.