A method for detecting pinching of a coupling hose between a tank and a gasoline vapor filter for a vehicle internal combustion engine, with the vapor filter being connected to the engine via a duct including a controllable bleed valve, includes at least one sequence of a step consisting in opening a bleed valve; a step consisting in acquiring a series of measurements of richness of a mixture entering the internal combustion engine over a period greater than a predetermined value, representative of a bleed period of the gasoline vapor filter; and a step consisting in comparing successive measured values and determining if a variation in richness from one measurement to the next remains below a pre-determined threshold for a group of measurements spread over a period greater than a pre-determined value.