PeteGPhil

not sure the make but yes it was coded. things have gone quiet again at present, all working OK but it did that before so could be ok for a month or so and then problems start again. Only time will tell

Ok so it wasnt the battery - been out twice since its been replaced and both times error messages and dash lights have come up.

I opted for a halfords battery for now as not sure how long I will hang on to it, and yes coded to the car. Over time two different garages have looked at it, Audi main dealership had it for 4 days, test drives computer, the works they could find anything (no faults came up whilst they had it either) and a local independent Audi dealer also had a good look at it another time same result. if the battery doesnt work I am probably going to have to wait for it to die or the fault becoming more frequent before being able to track it down

Hi both So new battery is on, only time will tell now, sometimes I have had to wait a month or so before seeing the errors, hopefully I wont see them again. I will update the thread from time to time. I am a bit old school so for me I only changed the battery when the car wouldnt start - but modern electronics are so different.

Hi both thanks for the responses, it is certainly something I hadnt considered. The battery always seemed fine absolutely no problem starting etc etc ,but it is as far as I am aware the original and as you say a relatively easy thing to eliminate. I will look at doing that and see what happens

this is a very challenging one - I have a 2013 A6 Avant SE 2.0l TDI. I have for some time had a strange electrical problem which means I loose most of the driver assist functions. (stability control, tyre pressure monitor, hill start assist) at first it seemed to be linked to water/damp, but over time has become more frequent. It would occur at various times, whilst driving, when starting up and originally about once every couple of months, although now it is weekly. Yesterday was a clear example (it was very hot) - I left home about 9.00 and drove just over 50 miles, it was perfect. I stopped for about an hour, when i started up to go I got error messages about all the above plus brake system error, and no power steering, the engine management light was also flashing and the auto handbrake off didn't work (often during these periods when applying the handbrake I get "vehicle parked too steep"), and also no aircon. I drove about 20 minutes to my next destination, parked up for several hours. Got back in the car to return home - same issues again, then after a few minutes power steering came back, aircon started working and engine management light gone. I drove about 30 mins and stopped for 5 minutes, switch on to finish journey - everything cleared except hill start not available. Some other facts - sometimes but not always the faults clear when restarting, they rarely clear whilst driving. The computer (diagnostics) has said no faults, but that was when none were showing but also none in the history. a few days previously the faults had appeared during a 5 mile journey. SO any ideas where to start to look - it seems to me to be linked to items managed via the centre console area (Stabilisation control, stop start, hill start etc) but I am wondering if there is a module that controls all these functions or is at least a link between them. Thanks