i drive an audi a6 2.8 quattro and i think its my abs sensor because when u drive it you can go as fast as you want but when you hit the brake when it gets to the speed of 15-10 doing down it starts to pulsate the brake pedal but no abs light is on any help? and how much would it cost to get fixed?

 

Sounds like the ABS sensor to me, or the "tone ring" which is a part of the sensing system located on the CV joint. Eventually the ABS light may or may not come on if you can get the problem to occur repeatedly. To find out which specific sensor it is you need a VAG COM, or you can take it to a shop. Im not sure what they would charge for labor but the sensor is just over 100 bux brand new if i remember right.