While we retrofit led light bulb on auto, we normally meet some problems like error code on OBC or led flickering. The led light bulb is brand-new and also good, why do these troubles occur on vehicle? At this time, we need to recognize our automobile system in order to realize the concern better. In our auto, there is a can-bus system to remind us mistake happens in order to shield the vehicle. But exactly what is can-bus is? To comprehend easily, we could envision that the vehicle resembles a human body. The Controller Area Network system (can-bus) is the nerve system. It facilitates interaction between all parts of the body. Digital control units(ECU) are connected to the can-bus. So it acts as a main networking system. In a contemporary auto there are about 70 ECUs. The CAN currently permit ECUs to communicate with each other without complex dedicated wiring between, enabling any ECUs to communicate with the whole system without triggering an overload to the controller comput