The key selector is the part of a car that lets the user to command the engine ignition or the powering of several other components. The thesis work product is the Matlab/Simulink model of the algorithm that recognizes the mechanical position of the key selector based on the corresponding electrical signals. First, the behaviour of the mechanical key rotation has been simulated with a Simulink model. Secondly, the key selector electrical signals has been studied and an equivalent electrical circuit in PSpice has been realized to obtain the simulated voltage signals acquired by the ECU. Then, based on the Model Based Design approach and following the principles of the AUTOSAR architecture, the model has been implemented.