I have a 1999 S4 Avant 2.7T. For some months now the ABS seems to be activating when braking gently to a stop. There is a distinct clonk, clonk, clonk which you can both feel and hear. Sounds like it is coming from the front wheels. My local Audi dealer could not fix it due to the fact that there are no error codes! They tried new wheel sensors but they had no effect. The system has been bled and new discs and pads have been fitted. The ABS pump may have been the problem so I sent it off to be refurbished. Still no joy. I read somewhere that you have to use a VAG tool to bleed these pumps but since my model was before ESP was introduced I don't see the option to bleed using VAG-COM. Any help would be greatly appreciated.

 

did you try new abs sensors?

 

The dealer tried new sensors but the problem remained.

 

how new are your tires. worn tires have an effect to

 

did your dealership replace all four sensors? if it happens just before coming to a complete stop (~5mph), then that definitely sounds like an abs sensor. sometimes they aren't bad, but they're just installed incorrectly (not seated quite right)

 

check the rotors for any type of damage?

 

I unfortuneately, have the same problem on my 99 A4 2.8. I have yet to see the root cause on what fixed the problem from someone. Anyone finally get this problem fixed?

 

Faulty ABS control unit?

 

ABS light on?

Are you getting any DTC's?

 

do you have the same size tires all around and also what size wheels do u have on the car