The electronic control unit of body control module (BCM) is used more and more in automobiles, and the data communication between electronic devices is also increasing. At the same time, the extensive use of these independent modules not only improves the comfort of vehicles, but also brings problems such as increased cost, rising failure rate and complicated wiring. Therefore, it is necessary to design a powerful control module to realize these discrete controller functions and control many electrical appliances, which is BCM. ECU (Electronic Control Unit), also known as "trip computer" and "vehicle computer". In terms of use, it is a special microcomputer controller for automobiles, also called a special single chip microcomputer for automobiles. It consists of microprocessor (CPU), memory (ROM, RAM), input/output interface (I/O), analog-to-digital converter (A/D) and large-scale integrated circuits such as shaping and driving, just like an ordinary single chip microcomputer. The function of the electronic control unit is to calculate, process and judge the information input by the air flowmeter and various sensors according to the programs and data in its memory, and then output instructions to provide the fuel injector with electric pulse signals with a certain width to control the fuel injection quantity. The electronic control unit consists of a microcomputer, input, output and control circuits.