Hydraulic braking system for a vehicle and corresponding operating method

A hydraulic brake system for a vehicle, comprising:

• a brake master cylinder;
• a plurality of wheel brakes;
• a hydraulic unit comprising at least one brake circuit configured to modulate brake pressure in the wheel brakes;
• and
• a bistable solenoid valve assigned to at least one wheel brake of the plurality of wheel brakes, the bistable solenoid valve looped into a corresponding fluid duct directly upstream of the associated wheel brake and, in a currentless open position, the bistable solenoid valve enables the brake pressure modulation in the associated wheel brake and, in a currentless closed position, the bistable solenoid valve encloses a current brake pressure in the associated wheel brake,
• wherein a hydraulic force which is brought about by way of the enclosed brake pressure has a seat-opening effect in the bistable solenoid valve, and
• wherein the hydraulic brake system has a negative pressure function which opens the bistable solenoid valve in the currentless closed position, and brings about a pressure build-up in the corresponding wheel brake via a fluid pump if the brake pressure which is enclosed in the corresponding wheel brake undershoots a predefined second threshold value.