System and Method for Controlling a Vehicle Brake to Prevent Vehicle Roll Away

A brake control system for a vehicle includes electropneumatic modules that control fluid pressure to brake actuators for wheel brakes to apply and release service and parking brakes. A parking brake controller (i) determines whether the parking brake is in an applied state or a released state, (ii) whether a speed of the vehicle meets a predetermined condition relative to a predetermined speed and (iii) whether a command to move the service brake to an applied state has been issued by a service brake controller. When conditions (i), (ii) and (iii) are present, the controller identifies an absence of communication on a communications bus indicative of a failure in the service brake controller and/or the communications bus and thereafter generates a control signal configured to cause to move the parking brake from the released state to an applied state.