A fluid control valve having a holder body that has a receptacle containing a piezoelectric actuator unit and a hydraulic coupler module that has at least one positioning piston and at least one actuating piston that is operatively connected to the positioning piston via a hydraulic coupler and actuates a valve-closure member that cooperates with at least one valve seat and in the closed position, prevents a flow of fluid from a valve chamber to a return conduit. The positioning piston is guided in the receptacle by means of a seal.