Vehicle hybridization allows for better performances and reduced tailpipe emissions at the cost of a more complex architecture, this is the starting point of the thesis work that analyses the software impact transitioning from a conventional Internal Combustion Engine (ICE) vehicle to a hybrid vehicle with a focus on the new torque path structure, which represents the flow of signals connecting the driver’s demand, in terms of accelerator pedal engagement, to the final torque quantity delivered by the ICE and Electric Motor (EM). Mild Hybrid Electric Vehicles (MHEV) operate in Charge Sustaining (CS) mode to keep the State of Charge (SoC) of the High-Voltage battery between two threshold values in every operating condition thanks to the regenerative braking feature that allows for battery recharging by means of conversion of kinetic energy in electrical energy using the bi-directional possibilities of the EM.