Method and system for quickly detecting an absence of a leak in a fuel system

It is proposed a method for detecting rapidly an absence of a leak in a fuel system mounted on board of a vehicle, the fuel system comprising a pressure sensor adapted to measure pressure comprised within a predetermined working range of pressure. The method is such that it comprises the steps of: a) measuring (S3), by means of the pressure sensor, a pressure in the fuel system at a predetermined time; b) detecting (S4) an absence of a leak when the value of the measured pressure lies outside a range of pressure values which upper and lower limits are set as a function of a predetermined noise and the predetermined working range of pressure.