An electronically controllable pneumatic braking system for a vehicle includes a first control unit for a primary system and a second control unit for a first fallback level, and a monostable fail-safety valve unit which pneumatically connects a main port, which provides a first pressure, and a failure brake port. The fail-safety valve unit is connected to both control units and in a fault situation, power failure and/or diagnostic situation of the control units, provides the failure brake pressure for triggering a failure braking operation. The failure brake port is connected to the primary system and/or to the first fallback level upstream of a functional pneumatic unit of the primary system and/or the first fallback level, in such a way that both front axle service brake actuators and rear axle service brake actuators have a brake pressure applied thereto in order to implement the failure braking operation.