ZEVonUDS – OBD Diagnostics now for electric vehicles

25th April 2023

Sheryl Miles

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Vector Informatik offers a directly usable tool chain for the new diagnostic standard ZEVonUDS (SAE J1979-3).

The new standard introduces on-board diagnostics (OBD) also for electric vehicles / zero emission vehicles (ZEVs) and plug-in hybrid electric vehicles (PHEVs). Tools must be made fit for the new standard across all areas of vehicle diagnostics.

The SAE standards of the J1979 family describe in detail how OBD data is read from vehicles using an external diagnostic device ("scan tool"). This can be used to monitor functions in ECUs that have an influence on vehicle efficiency. The monitoring functions must be available whether emissions are caused directly by an internal combustion engine or indirectly by the generation of electricity to charge a traction battery in the vehicle.

SAE J1979-3 is a subset of the UDS-based On-Board Diagnostics introduced under SAE J1979-2 OBDonUDS. According to the SAE standard and the California Air Resources Board (CARB), all ZEVs and PHEVs must support ZEVonUDS in the US market from model year 2028 at the latest.

ZEVonUDS is being introduced to read out specific measurement data from electric vehicles with a scan tool. This includes, for example, the Battery State-of-Health, which is used as a quantitative parameter in determining the residual value of an electric vehicle. CARB uses the SAE J1979-3 standard to record repairs on electric and plug-in hybrid vehicles registered for sale in California.

New challenges arise for both the ECU software and the diagnostic testers, especially for startups in the ZEV field. These startups did not have to support on-board diagnostics in the past – but need to implement ZEVonUDS over a relatively short timeframe. This requires a fundamental change in the ECU software. In addition, the new standard requires new development tools for specifying, testing, and applying diagnostics.

Vector already offers an integrated tool chain for the new SAE standard ZEVonUDS. 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 diagnostic tester ("scan tool") with Indigo.