The Performance of Electric Hybrid Transmission system is controlled by Electronic control unit (ECU). ECU Casing, which packages Printed circuit board (PCB) with components soldered on both sides, have to protect the PCB and components from Thermal DamageDust and Water ingressVibrations in the vehicleAir-Pressure fluctuationsPaper enlightens Product development Architecture of ECU Casing explaining all Phases of product cultivation from processing of inputs till validation of the product.Requirement Analysis being first phase, analyses all PCB requirements, mechanical requirements related to product certification.Architecture Conceptualization being second phase, analyses layout optimization, Material Category, Manufacturing Category, Production Process, Material Grade.Design being third phase, analyses all aspects of Engineering Design, Manufacturing Design, and Feasibility Design. Engineering Design elaborates cross functional study between Thermal aspects, Structural Rigidity, Aesthetic Compliance, Vibration behavior, Ingress Protection Compliance, Air-Pressure Management of Casing assembly. Manufacturing Design elaborates features related to manufacturing process. Feasibility Design elaborates design in terms of manufacturing, servicing.Validation being fourth phase includes prototyping, physical testing, Comparison with CAE results and Optimization.