A retrofit kit is a system that allows the conversion of an internal combustion engine vehicle into a full electric one. This thesis work aims to further develop a custom algorithm for a vehicle control unit, which is part of a conversion kit to be installed on vintage cars. In particular, the development of the functionalities related to the powertrain control module (PCM) is addressed. The algorithm is developed using the LabVIEW environment and is tested according to the model-based design approach. In the first section, the requirement analysis of the PCM algorithm is carried out and its first implementation is proposed.