A Volkswagen Jetta two valve car in 2005. The car owner reflected that the car because of the bad braking effect, nearly crash, find other repair plant repair, before cleaning, rear wheel sensor invalid, come to our factory repair. After trial run, it was found that the ABS acted too frequently and the braking distance was long during emergency braking. All the time to stop, ABS pumps are moving frequently. The owner felt the brake failure.