found this info not sure if it will help but worth a try:
The prime issue to note is that a poor / weak battery will cause this - I note whats been done in the battery area , so thats that.
What I want you to do now is, ensure the battery is fully charged, then , keys, out of the vehicle- remove the battery leads -and clamp the connector ends to each other. Tie with a wire if they wont reach each other - and leave like that for 30 mins. Then , disconnect them - leave off the battery for a further 30 mins - then re connect them to the battery. To explain, this is a re boot procedure for the control modules. If the system has just glitched, as they tend to - this procedure will usually sort it.
IF not - then Im afraid you have control module failure- there is just nothing more you can do in a Diy basis at that point Im afraid - it has to be connected to Audi diagnostic equipment to trace / id & sort the issue you have.. there is just no other way if you get to this point working through the above.. Im sorry if thats the case... I have seen this before.. there is just no other way then Im afraid.. It will need a new module which when fitted, has to be programmed to the vehicle using Audi equipment - so again, if you do get to this point, there is just nothing else you can do on a Diy basis - sadly, thats how its going these days --
So work through as above on this now - By all means get back to me if you need / wish to discuss it further... I hope the above does work for you -
I sincerely hope the above all helps you and helps with the understanding of the problem you have -and what needs to be done to cure this ...
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