If you use Vagcom ( or similar ) it will tell you which sensor has a problem. It may not be the sensor itself it could be the ring on the driveshaft which is either broken, correded or just covered in carp ! The normal braking system is seperate from the ABS and will still function perfectly ( some may say better :unsure: ) without it, especially in icy weather......my personal opinion....bloody hate ABS. However as mentioned it is an MOT failure if your light is on......and hence no ABS.