VW ABS sensor. The ABS sensor is mounted to the rear axle. Without a properly functioning sensor your ABS computer will not work properly. This can lead to some dangerous situations in the rain and snow, especially if you've never driven without ABS. Replace your faulty ABS sensor with this original equipment quality part. Fits either side.
The VW ABS sensor is a critical component to your vehicles driving system. If your Jetta, Golf, or New Beetle has ESP, the sensors relay information to the computer so that it can make adjustments. If you want to know exactly what is wrong with your ABS system without going to the dealer you need a VAG-COM scan tool to read the fault codes and diagnose from there. This ABS sensor is triggered by the ring around the wheel bearing assembly shown below.