I have the same problemwotj my 00 passat 4 motion , and the vw clinic told me that just to keep it easy on the brakes , try not to stop in one second or your abs module may lock the rear axel.
Regarding to the solution of the problem , try to find another VW clinic but not the dealer , because the will charge you an eye of the face , just to tell you the problem, and do not even talking about the labor to fixed , Here in Houston dealer charges 95 plus tax per hour , when in the vw clinic i pay 42.5 for the diagnostic complete, and since i do mechanic stuff a little, they even help me by telling me what to do to so it myself.
I have found a ABS module electronics, for 100 dls with shipping , when the dealer wanted 525 for that thing. look on the Ebay for it.
Hope that helps,bye
