ESP Fault Solved!
 

Finally I took my A8 to a shop to be looked at. The error I was getting was a random ESP Fault that would turn off my cruise control, traction control and along with an annoying beep. So i took it to a European car shop and had it looked at, and only problem seemed to be the brake light switch. Still have the original battery in the car, which was reading low voltage so had that replaced as well. Just in case anyone else comes across this problem here's your fix :)
The brake light switch was only $22, and the battery was an unfortunate $190 :( a nice interstate battery though :). $39 installed and coded.
Cheers!

Another reason why you should buy a vag com, a brake light switch would have thrown a fault code.

the vag coms still expensive :), wheres the cheapest I can find one?

Well the software is a free download, but the cable is around $300. You can find cables on ebay for a lot cheaper, but they don't always work.........go figure.

Just a note for all A8's. please don't hesitate on check/replacing ur TB 75000 mls or before.. I almost ruin my engine because the belt was very loose due to tensioner failr at 74000 mls..Please have done right not cheap at ur friendly shop GO DEALER because the will replaced all required parts I tried the cheap then the the Dealer notice cam seal leaking..Hear we got another $900-1000 bill.

^^^Im guessing you didn't read the stickys before posting that, i would hope thats common knowledge, except for the dealer replacing everything LOL! Doubt it, thats not how dealerships work.

I for one never go to dealerships. They are a rip off, and most of the time they are the ones saying Uhm i don't know this computer's so complicated it could be so many different things causing this" other places are like heres your problem. Boom! $50 cheaper
thankyou!