This paper describes the integrated design of the pressure control in a common-rail injection system. Mechanical elements and the embedded controller are considered as a whole, using a multidisciplinary approach to modelling and simulation. The virtual prototype, which provides the detailed geometrical/physical model of the mechanical parts, plays the role of a surrogate of a reference hardware prototype in reduced-order modelling, validation, and/or in tuning the control parameters. The results obtained by the proposed approach are compared and validated by experiments.