Yeah, I know what it means. When I've gotten it in the past, it was constant and I needed pads. Now I get this message intermittently though. Brakes have about only 18k miles on them - raybestos QS ceramics. But the message comes on right as I start the car sometimes, after a few minutes sometimes, after a long time sometimes, or sometimes not at all. Seems like if I've worn through the sensor the message would be constant. Could it be a bad wear sensor? Or do these ceramics really only last 18k?