Hi Marty,

Yes, I only seem to have this problem in the winter as well. Especially after a snow storm and salted roads. There is one sensor on each front wheel.

Here's the way I approached the problem, although there might be other methods. I figured I might as well check my brake pads anyway.

1. Jack up the front and rear of one side of the car. Use jack stands as well. The reason that I jacked up the rear was that I figured I might as well rotate the tires at the same time since I was already removing the fronts.
2. Remove the front and rear wheels, rotate them.
3. Open the brake fluid reservoir cap. Squish down on the front brake caliper/brake pads with pliers to help open it up for removal.
4. Remove the front brake caliper and support the calliper away from the rotor.
5. Remove the front brake rotor. You might have a small set screw in the rotor that helps keep it in place.
6. With the rotor out you will see a 3/4 inch or so long metal post that is magnetic and totally covered in metal fuzz and in my case nasty rusted metal crud. I took brake cleaner, an old tooth brush, a couple of rags to clean the sensor. There is also an indexed wheel that the sensor reads as the wheel hub spins. This also was loaded with gunk so I thoroughly cleaned it.
7. Put the brake rotor back on.
8. Put the brake caliper back on.
9. Put the tire back on.
10. Lower car and tighten lug nuts.
11. Don't forget to tighten the cap back down on the brake fluid reservoir.