Mine had the same problem, and I checked the rotors and the cap, and they were rusted and corroded. I bought new rotors, and new rotor caps, and my problem went away. I thought It was a wire or something, but after i fixed the rotor problem, everything went away. Myc ar hasnt done that in the past 5 months since it last did it, so u might wanna check that out really quick, u never know.