The definition of a product’s dimensional characteristics is a challenge in project development in the automotive industry due to its construction complexity, in which several components from different development areas and suppliers must interact in a final product. Dimensional characteristics are understood as being those related to tolerances, gaps, fit, matching between parts, product specification and control charts. In order to allow the product to be assembled without the need of further adjustments and within the time determined for its assembly, it is necessary that all these characteristics be specified, verified and confirmed in the individual parts and in the composed assemblies of those parts. This study proposes a system that enables the identification, evaluation, definition and control of dimensional characteristics in the development of a new product, from the initial phases of the project to the mass production, using different tools and concepts of tolerance analysis. The system is exemplified through its application in two actual production cases (taillight and front-end) in a car assembly company.