[EspressoLounge12]

I've seen a hand full of European cars with wear strips (like Craig describes) that basically break a connection and cause a light on the dash once the pads wear beyond a certain point but I've never heard of a "sensor" that detects brake pad wear.

Looking at the schematics for the brake system, there's no mention of a sensor at all.

Can you post a picture or link to a part so we can take a look?

Like Karl said, there's a "squealer" on almost all modern brake pads that cause the high-pitched nails-on-a-chalkboard sound that spells impending doom for your rotors.

-Brian