I hope this helps somebody:

My 2002 A6 2.7T "Brake" light on the dash would flash and beep, whenever I would make a sharp right turn. This is what my dealer's advisortold me:
If you are making a sharp right turn and your "Brake" light flashes and you hear 3 or 4 beeps, it is most likely that you are low on brake fluid.
If at "any time" the Brake & ABS flash and you hear or do not hear audible beeps, it is most likely your ABS control module.
Ihave total confidence in this advisor. He is right 100% of the time.
Senerio #1 $7.00.
Senerio #2 $400.00.