Electrohydraulic vehicle braking system having redundant hydraulic pressure generation, and method for operating the braking system

A method for operating an electrohydraulic vehicle braking system having wheel brakes, comprising the following:

• an electrically controllable first hydraulic pressure generator;
• a first valve device for each of the wheel brakes, each first valve device having a first valve, wherein in an electrically uncontrolled state the first valve device separates its associated wheel brake from an output of the first hydraulic pressure generator, and in an electrically controlled state the first valve device connects its associated wheel brake to the output of the first hydraulic pressure generator;
• an electrically controllable second hydraulic pressure generator;
• and
• a second valve device for each of the wheel brakes, each second valve device having a second valve and a third valve, each second valve being located between an output of the second hydraulic pressure generator and its associated wheel brake, each third valve being located between its associated wheel brake and a first hydraulic fluid reservoir, wherein the first valve device and the second valve device of their associated wheel brake are arranged in parallel to one another and for their associated wheel brake the second valve and the third valve are downstream of the first valve;
• the method comprising the step:
• electrically controlling the first valve device to an open position and the first hydraulic pressure generator to build up a brake pressure at the wheel brake associated with the first valve device, wherein the second valve and the third valve of their associated wheel brake are in a switching state that prevents escape of hydraulic fluid from the associated wheel brake.