: Identifies the failed component (e.g., Engine Oil Pressure).
: Lists Previously Active DTCs , providing a history of faults that have occurred but are no longer active. sae j193973 pdf exclusive
The document is the definitive standard for the diagnostic application layer in heavy-duty vehicles, such as trucks, buses, and agricultural machinery. It defines the specific messages, known as Diagnostic Messages (DMs) , and the Diagnostic Trouble Codes (DTCs) used to report and troubleshoot issues across a vehicle's Electronic Control Units (ECUs) . Current Version and Access : Identifies the failed component (e
: Describes the nature of the failure (e.g., data valid but above normal range). : Identifies the failed component (e.g.