Recent content by Bercilak

Most likely the servo pump was commanded off by the ECU, its electric, so unlike an ICE car. You are right that dual circuits should not both fail so you always have front or rears. Citroen used to put the handbrake on the front wheels - great system that as you could brake under any circumstances.

With regard to the brakes, presumably there is some sort of electric vacuum pump involved, so if that was one of the failing systems there would be no servo assist. That would give a solid feeling brake pedal but little or no braking action.