Vector Informatik has developed a tool chain for the emerging ZEVonUDS standard for onboard diagnostics (OBD) in EVs (writes Nick Flaherty).

The standard, SAE J1979-3, details how OBD data is read from vehicles using an external diagnostics device called a scan tool. This can be used to monitor functions in ECUs that have an influence on vehicle efficiency, and the monitoring functions must be available whether emissions are caused directly by an IC engine or indirectly by generating electricity to charge a traction battery in the vehicle.

This zero-emissions vehicle (ZEV) version follows on from the OBDonUDS SAE J1979-2 standard to read out specific measurement data from EVs using a scan tool. This includes, for example, battery state of health, which is used as a quantitative parameter for determining the residual value of an EV.

All battery, hydrogen and hybrid vehicles must support ZEVonUDS in the US market from model year 2028 at the latest, and the standard is also being used to record repair data on electric and plug-in hybrid vehicles registered for sale in California.

However, this creates challenges for both the ECU software and the diagnostics testers, especially for smaller companies developing e-mobility platforms. These start-ups did not have to support OBD in the past but now need to implement ZEVonUDS over a relatively short timeframe. This requires a fundamental change in the ECU software as well as new development tools for specifying, testing and applying diagnostics.

Vector’s tool chain supports all phases of development with ZEVonUDS, from specification of the relevant OBD content to implementation in ECU software with MicroSAR. Validation of the code is handled in the CANoe.DiVa tool, using the Indigo diagnostics tester scan tool.