SAE J1939-73 is a specific sub-standard that defines the processes, messages, and data formats required to perform diagnostic functions on a J1939 network. It bridges the gap between raw vehicle data and the technician, allowing diagnostic scan tools to read fault codes, clear memories, and run component tests.
For the most up-to-date and accurate information, always ensure you are referencing the latest version of the standard, currently . Obtaining the official PDF from a standards body is the best way to ensure you have the definitive specification for your work.
A 1-bit flag that defines the byte alignment of the SPN within the message architecture. 2. Diagnostic Messages (DMs)
Provides a history of faults that have occurred but are no longer active. DM3 (Diagnostic Data Clear): Used to reset or clear previously active fault history. DM11 (Diagnostic Data Clear/Reset for Active DTCs): Used to clear active faults from the ECU memory. DM12 (Emission-Related Active DTCs): Sae J1939-73 Pdf
The document is a critical technical standard that defines the Application Layer for Diagnostics within the broader SAE J1939 protocol suite. It standardizes how heavy-duty vehicles—including trucks, buses, and agricultural machinery—communicate diagnostic information between electronic control units (ECUs) and external service tools. Overview of SAE J1939-73
It works alongside SAE J1939-71 , which specifies general parameter placement in data groups.
The official platform to purchase and download the authorized, up-to-date PDF version of SAE J1939-73. SAE J1939-73 is a specific sub-standard that defines
The J1939 standard is a collection of documents, each detailing a specific layer of the communication architecture. While J1939-71 defines the general vehicle application layer (e.g., how to send engine speed or vehicle speed data), J1939-73 focuses specifically on diagnostic services. It doesn't reinvent the wheel for CAN communication, as the network typically uses the CAN data link layer (ISO 11898-1) with extended 29-bit identifiers, while J1939-73 focuses on the higher-level diagnostic interactions. It is primarily defined for compatibility with third-party diagnostic tools, ensuring a consistent interface for vehicle data across different equipment brands.
Reading and writing specific memory locations within an ECU for calibration or software flashing.
A 5-bit number describing the type of failure observed (e.g., FMI 3 means voltage above normal, FMI 4 means voltage below normal). Obtaining the official PDF from a standards body
J1939-73 standardizes the control of dashboard indicator lamps. It defines the states for:
The SAE J1939-73 standard has various use cases in the automotive industry, including: