Research On Remote Vehicle Condition Monitoring And Fault Diagnosis System

With the substantial growth in car ownership in China, car monitoring is more and more important. With the announcement of country IV stantard of vehicle emission, all vehicles must be equipped with On-Board Diagnostics (OBD) system. This paper researched on how to plug and perform vehicle condition monitoring and fault diagnosis without any car modification, just use the OBD-Ⅱsystem which is forced to be installed by the country.The entire program of remote monitoring and diagnostic system is analyzed and compared with other existing programs. Then ISO-15031 standard, the physical interface definition and communication protocols of OBD-Ⅱsystem is introduced. The measure of getting needed data from the DLC interface is also analyzed.The implementation of the remote monitoring and diagnostic system is introduced for the view of hardware and software. Hardware circuit of STM32 master system and interface circuit of ELM327 OBD-Ⅱdata translation module, SIM300 GPRS communication module, C3-470C GPS positioning module and BCM body control module are designed. The transplant process ofμC/OS-Ⅱembedded operating system andμC/GUI user interface are introuduced. Also, the communication protocol and data formats proceeding of ELM327 module are introduced to achieve using SIM300 for GPRS DTU transparent data transfer and sending or receiving text message. Vehicle GPS location information can be got from C3-470C. A PC software programmed by LabVIEW was designed and implemented to connect with SIM300 for bidirectional data transmission.Finally, a test on the remote vehicle condition monitoring and fault diagnosis system was performmed with an actual car. The test results showed that the whole system was in line with the expected. The data read from OBD-Ⅱsystem can be resolve into vehicle status parameters and displayed on the LCD screen. Also remote data server could establish a connection with SIM300 and receive vehicle status parameters and GPS location information.