i had this recently after getting brake caliper changed,random stop warnings with no more info,then i had other caliper changed by a different garage and they screwed up the job and basically all my brake fluid pissed out eventually throwing up a "stop" followed by "brake fluid" but according to garage that fixed it properly if i'd have used the brakes a few more times before i rolled slowly up to the garage my braking would have involved a wall or something equally as nasty