To read DTCs from a specific ECU, you must send a DM20 request. J1939-73 specifies that simply listening to DM1 may miss intermittent faults.
Note: The SAE J1939-73 document is intellectual property protected by copyright and must be legally purchased directly from the Society of Automotive Engineers (SAE International) website. Summary of Benefits Implementing SAE J1939-73 correctly ensures: Sae J1939-73 Pdf
Since the standard is copyrighted and sold by SAE International, obtaining the PDF from a legitimate vendor is crucial for accuracy and to ensure you have the latest version. The most direct way is to purchase it from official standards resellers. Various versions of the SAE J1939-73 standard, including PDF and hardcopy formats, are available for purchase from authorized distributors. Some distributors offer online subscriptions where users can search, view, and download PDF documents, with automatic updates when standards are issued or revised. To read DTCs from a specific ECU, you
You can also find the SAE J1939 protocol collection, including the J1939-73 PDF, on educational repositories and documentation sites that offer it for free alongside other parts of the J1939 standard. Some distributors offer online subscriptions where users can
(Exact PGN numbers and field formats are in the SAE J1939-73 specification—consult the standard PDF for full byte-level definitions.)