SAE J1939-73 defines the SAE J1939 messages to accomplish diagnostic services and identifies the diagnostic connector to be used for the vehicle service tool interface. Diagnostic messages (DMs) provide the utility needed when the vehicle is being repaired. Diagnostic messages are also used during vehicle operation by the networked electronic control modules to allow them to report diagnostic information and self-compensate as appropriate, based on information received. Diagnostic messages include services such as periodically broadcasting active diagnostic trouble codes, identifying operator diagnostic lamp status, reading or clearing diagnostic trouble codes, reading or writing control module memory, providing a security function, stopping/starting message broadcasts, reporting diagnostic readiness, monitoring engine parametric data, etc. California-, EPA-, or EU-regulated OBD requirements are satisfied with a subset of the specified connector and the defined messages.
Rationale: Update Table 1 to reflect CSERS PGs and their SPs in support of the November 2022 publication of 13 CCR 1971.1, and to reflect comments on provisions made for China 6 Off Road. Add an SP, ignition cycle counter 2, to DM57 in 5.7.57. Add a new FMI into Appendix A. Improve text for DM11, DM24 and DM58 to address committee member comments.