A fail-safety valve unit of an electronically controllable pneumatic brake system for a vehicle is disclosed. The unit includes a main port for providing a first pressure, a failsafe brake port, and a failsafe brake valve. The brake valve is controllable by a control unit. The brake valve pneumatically connects the main port and the failsafe brake port when in an open position to output a failsafe brake pressure at the failsafe brake port. In the event of a fault, an electrical failure, and/or a diagnostic event of the control unit, the brake valve is in the open position and a failsafe braking operation of the vehicle is initiated through a failsafe brake pressure at the failsafe brake port by the brake system. The main port is pneumatically connected to a parking brake function to receive an output parking brake pressure or a pressure derived therefrom, as the first pressure.