With the continuous advancements in the automotive industry, there is an ever-increasing need to ensure the reliability of the vehicles. This Master's degree thesis focuses to find a methodology for improving the software reliability in the electronic control units utilized into the CNH Industrial's vehicles. It is a global company formed by 12 brands, including IVECO S.p.A, an Italian industrial vehicle manufacturing company based in Turin. Starting with the definition of error, fault, and failure, the thesis continues with the summary of software development lifecycle models. In the further chapters, an overview of the verification and validation model has been provided, followed by a description of Agile methodology, DevOps methodology, and Model-based development.