Design of an information system for vehicle diagnostic trouble codes

Abstract

A system has been developed to communicate with the On Board Diagnostics system of a car using the Controller Area Network communication protocol. The system requests the stored trouble codes that might have been detected by the diagnostics system and sends them together with a Vehicle Identification Number to a remote server. The information is stored in a database on a remote server and can be accessed through a web interface. The web interface allows the user to find his car in the database together with the detected faults. The database also contains information about trouble codes, such as their symptoms and how to fix them. The system was developed on a development platform by Syntronic AB called Midrange and the final prototype consists of Midrange, a GPRS module to communicate with the remote server, and an LCD to display runtime information. The communication protocols and drivers were developed using the low-level software libraries that was provided with the STM32 microcontroller mounted on the Midrange board. Monitoring the communications while testing the prototype showed that the system works as intended and can communicate with cars from different manufacturers and deliver the data reliably to the database. The prototype system was compared with a commercial scan tool and testing showed that they both produced the same results.