As the number of vehicles is increasing day by day, the infrastructure requirements associated with vehicles are also become complex. Hence the count of ECU used in vehicles, in order to satisfy these requirements are growing. As a result complexity increases. The complexity of ECU can be reduced to a great extend by using a standardized architecture. Hence AUTOSAR (AUTomotive Open System Architecture) came into existence and got much popularity in the automotive domain. AUTOSAR is an open and standardized platform for automotive software. By using AUTOSAR standardization, scalability, increased quality and safety of E/E systems can be achieved. EcuM (ECU State Manager) implements the Ecu state management in AUTOSAR platform. EcuM is module present in system services layer of AUTOSAR. EcuM is responsible for initialization and de-initialization of OS and other basic software modules. It also manages all the wakeup events associated with ECU. This paper focuses on the design and development of EcuM module based on AUTOSAR 4.0.