This thesis in collaboration with AKKA TECHNOLOGIES has the aim to study the tracing of a vehicle telematic control unit to improve the detection of possible failures. The issue detection allows the programming of a correct maintenance plan to offer an optimal customer aftersales service. After an introduction about the current scenario of connected vehicles and on-board telematics, the study will start from the state of the art of CAN networks and the most used protocols to control and manage the flow of data transmitted from the various vehicle's ECUs to off-board services (i.e. backend and cloud applications). The core is the study of a test tracing with particular focus on the alerts (DTCs) related to vehicular issues and on the identification of two or more parameters that can help to define an algorithm to prevent the maintenance activity.