Method for checking the pressure of a hybrid vehicle fuel system

The method involves completely/partially releasing pressure in a fuel e.g. petrol, diesel and biomass, tank after providing safety duration when a thermal engine is stopped, where the fuel tank is made of a high density polyethylene material and a barrier layer of the fuel tank is made of ethylene vinyl alcohol/ethylene vinyl alcohol copolymer. A storage volume is defined by a plastic enclosure of the fuel tank, where the enclosure is reinforced by a fibrous internal/external reinforcement, local welding and solidarizing lower and higher walls of a reinforcing element i.e. pillar. The safety duration is defined by a processor according to a temperature value read by a sensor.