A brake system for actuating a plurality of wheel brakes in a normal non-failure braking mode and in a backup braking mode includes an MC-type power transmission unit having a first electric motor. An iso/dump control valve arrangement is associated with each wheel brake of the plurality of wheel brakes. A pump piston is associated with at least one wheel brake of the plurality of wheel brakes. The pump piston is driven by a second electric motor for selectively providing pressurized hydraulic fluid to the iso/dump control valve arrangement. At least one electric brake motor is operative to selectively drive a selected wheel brake. A first electronic control unit is operative to selectively control the first electric motor. A second electronic control unit is operative to selectively control the second electric motor. A third electronic control unit is operative to control the at least one electric brake motor.