The BCM Diagnosis Function Research And Application Based On CAN Bus

Widely used automotive electronic devices promote the development of communication network. Automotive communication network solved the problem very well that point-to-point communication electronic devices can’t satisfy the vehicle information sharing. Therefore, most domestic and overseas big auto companies and car electronic accessories companies have introduced the CAN communication technology. The CAN communication technology greatly improves data interaction performance of vehicles. At the same time, the diagnostic system based on CAN communication technology has been developing. The diagnosis function is an important part of ECU, the research and application of diagnosis function has important theoretical significance and practical value.This thesis based on the domestic and overseas documents and data in relevance field, firstly deeply researched CAN communication theory and the UDS diagnostic treaty, introduced the layer structure of ECU, the form of the frames, the arbitration mechanism and the way of diagnose communication, timer parameters, diagnostic servers and the format of DTC. Secondly, using ISO14229 international standards, the author set up BCM diagnostic specification which ruled the diagnose function of BCM and provided a basis for developing BCM diagnose function. Then the author designed BCM diagnosis function from hardware and software two parts. In the aspect of hardware design, it included power supply module, CPU module, transceiver module, signal acquisition module, circuit fault diagnosis and so on. In the aspect of software design, the diagnostic function execution strategy and process were designed from application layer and network layer two aspects. Finally, the author tested BCM diagnostic function and verified the feasibility and correctness.