J1939 and J1708 are distinct communication protocols used in heavy-duty vehicles. While often used alongside OBDII, they serve different purposes and have unique characteristics. Understanding these differences is crucial for diagnostics and data analysis.
J1708, an older standard, utilizes a single-wire communication system with slower data transfer rates. It’s primarily found in legacy heavy-duty vehicles and focuses on basic engine parameters. Conversely, J1939, a newer and more robust protocol, employs a two-wire CAN bus system enabling higher speeds and more complex data transmission. J1939 supports a wider range of parameters and functionalities, including engine, transmission, brakes, and emissions systems.
Due to the fundamental differences between these protocols, direct data conversion is not possible with a simple cable. Dedicated hardware and software are required to translate the data between J1939 and J1708. For instance, devices like the SilverLeaf Electronics VMSpc can extract J1708 data and display it on a Windows tablet.
Cost-effective solutions for accessing and displaying vehicle data include the ScanGauge D. This device offers basic data retrieval and display capabilities. More advanced solutions, like the VMSpc, provide comprehensive data analysis but come with a higher price tag.
For those with programming skills, J1708 to serial converters coupled with a Raspberry Pi and a touchscreen offer a customizable solution. Using languages like Python or PHP, custom software can be developed to display and analyze the desired data points. This approach requires a higher level of technical expertise but provides greater flexibility.
