My dash light for the brakes popped on, the ABS light is not. I checked the fluid and it was low as I figured, the last time I did brakes I just had the rotors turned and put on new pads, so I know it needs a full break job now. I topped off the brake fluid and the pedal still goes to the floor to try and stop this thing. The light did not shut off either. Is there some kind of wear sensor that I don't know about??