The contact had received a 2024 Acura ZDX loaner vehicle from the dealer. The contact stated that after backing into the driveway, pressing the park button, activating the electronic brake system, and exiting the vehicle, moments later the electronic braking systemwas deactivated, and the vehicle began to roll down the driveway. The contact was able to re-enter the front seat of the vehicle and press the brake pedal to stop the vehicle. The cause of the failure was not yet determined. Upon returning the vehicle to the dealer, the dealer was informed of the failure. The manufacturer was not contacted. The failure mileage was 3,700.