I have for sometime had problems with the traction control light staying on and not going off.
So after a little investigation and digging around I went ahead and done this, from the two below images you can see the location of the sensors both front and rear:
Front (item 7)
Rear (item 11)
After jacking the car up and taking the wheel off, these are easily found on the back of the hub.
To remove mine I had to take not only WD40 to it, but also had to use a long screw driver so I could use it to give me enough leverage to slide the sensor out.
Once the sensor is out I just gave it a good clean and replaced, if you need to remove the sensor and replace just follow the cable to the grey socket and disconnect.
Al