Study Of Automotive Powertrain Diagnostic System Based On K-line

With the increasing complexity of electronic control systems on the vehicles,special fault diagnostic tools have been used in automotive diagnostic technology. The current on-board diagnostic system can monitor the systemic parameters of automotive electronic control system continuously. This kind of diagnostic system can memorize the intermittent parameters of each sensors and actuators,so that it would be easier and faster to find out the faults. The communication protocols used by diagnostic system, the communication criterions which should be followed between vehicles and diagnostic tools,and the trouble codes and how to get them are described in detail in OBD-Ⅱstandard. Now most of the vehicles have adopted the OBD-Ⅱfault diagnostic system.The thesis describes several self-diagnosis program based on K-line on power system, and by studying the communication protocols (ISO-9141,KWP2000)and diagnostic protocol (ISO-15031) deeply, it puts forward a plan of automotive power train diagnostic system based on K-line, including the interface circuit and software programs. The hardware includes transferring the data signals of OBD-Ⅱto USB signals. The device via a dedicated protocol conversion chip TL718 connect OBD-Ⅱsystem to read fault codes and other data stored in the car, then by PL1303HX chip it communicates with PC through USB port. The software includes acquiring and analyzing the ECU data and fault codes, dealing with request messages,respond messages, analyzing and displaying the data. The configuration between LabSQL and database is linked through ODBC connection. Users need to specify the ODBC data source name and drive program. So before using LabSQL, we need create a DSN in ODBC in windows operating system. That is, the connection between LabSQL and database Access is established on DSN. LabVIEW record the acquired data into the tables in Access by the connection for subsequent analysis.