To reduce global warming, Honda has been worked on emission reduction and fuel efficiency enhancement by applying fuel injection systems. The productivity enhancement and cost reduction are strongly demanded in developing countries as the market is expanding. To enhance productivity and reduce cost of ECU, application of the semiconductor production method has been started for printed circuits with edge connectors. However, products that fully meet the requirements of us have not been realized so far. The ECU developed this time has a structure shielding the whole PCB package except the edge connector terminals. Thus, the waterproofness required for an ECU has realized, as a standalone component, as the first in the world (by Honda survey). To achieve that, we developed transfer molding dies equipped with a unique mechanism never been applied. Moreover, we developed an epoxy resin that eliminates the after cure process. Thus, productivity of 5 times over conventional was realized with a multi-cavity molding capable of moldings more than 10 pieces at a time. Furthermore, a new waterproof card-edge connector was developed, in which a half pipe type terminal providing a stable contact resistance, even with a low contact pressure, and a slider structure that enables reliable coupling operations were adopted. As a result, a vibration resistance that exceeds conventional performances was realized, and ECU attachment/detachment in a narrow work space was made possible. By applying the measures described above, the total cost of the ECU and the connector was reduced by 20%.