Method and System for Detecting a Leak in a Fuel System

It is proposed a method for detecting a leak in a fuel system of a combustion engine comprising a fuel tank. The method is such that it comprises the steps of: obtaining a first set of data comprising at least a pressure data measured in the fuel system at a first time; adding energy to fluids contained in the fuel system, said energy being produced or wasted by means already present on board the vehicle for other purposes; obtaining a second set of data comprising at least a pressure data measured in the fuel system at a second time; determining the presence/absence of a leak in said fuel system by calculating a predetermined function on the basis of said first and second sets of data.