OBDonUDS – What’s Behind the New Diagnostic Standard?

by donpedro

Figure 1: The new OBDonUDS standard will be introduced in 2023 and will be mandatory from 2027. Image copy right: Vector Informatik

Vector offers a ready-to-use toolchain for the new diagnostic standard SAE J1979-2 (“OBDonUDS”). The new standard will be introduced in the USA from 2023 and will be mandatory from 2027. The SAE J1979 standard describes in detail how On-Board Diagnostics (OBD) data may be read from a vehicle using an external diagnostic device. In the future, the new OBDonUDS standard (SAE J1979-2) requires the use of UDS (Unified Diagnostic Services) for reading out OBD data. Tools must be made fit for the new standard across all areas of vehicle diagnostic development.

In almost all road vehicles, compliance with emission limits is monitored continuously and over the entire life cycle by means of On-Board Diagnostics (OBD) as required by law. As described in SAE standard J1979, OBD data is read from the vehicle using a so-called scan tool. The freshly updated revision of the SAE J1979-2 standard (OBDonUDS) now prescribes the use of UDS (Unified Diagnostic Services) for reading out OBD data as well. UDS is standardized in ISO 14229 and has been used for many years for manufacturer-specific diagnostic content outside the scope of OBD. Revision of the diagnostic protocol for OBD became necessary because unique identifiers ran out in several places due to length restrictions, e.g., for DTCs (Diagnostic Trouble Codes). Especially within the fault memory, data structures have been extended to allow more details on individual faults to be queried. In addition, the correct functioning of an OBD system may now be monitored more easily with the help of new monitor activity data.

The implementation of OBDonUDS also requires a new implementation of the diagnostic software in the vehicle. In addition, new development tools will be required for specifying, testing, and applying the revised diagnostics. Vector already offers an integrated tool chain for the new SAE standard OBDonUDS. This supports all phases of development, from specification of the relevant OBD content with CANdelaStudio, through implementation in ECU software with MICROSAR and its validation with CANoe.DiVa, to application in the OBD diagnostic tester (“scan tool”) with Indigo.

More information: www.vector.com/obdonuds


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