A method and an arrangement for monitoring a deceleration function of a control unit of a motor vehicle affect as little as possible the operability of the control unit in the case of a fault. The deceleration function of a control unit (1) of a motor vehicle inputs a vehicle deceleration independently of the actuation of a vehicle brake operator-controlled element. The input is transmitted via a deceleration interface (5) to a brake system (10) of the vehicle to realize the input. A check is made as to whether a brake intervention of the brake system (10), which is initiated by the deceleration function, is permissible and, at first, only the deceleration function is deactivated when the brake intervention is impermissible.