OBD in Zero-Emission Vehicles

SAE J1979-3 (ZEVonUDS) makes On-Board Diagnostics (OBD) mandatory for Zero-Emission Vehicles (ZEVs). In the U.S., a phased implementation is in effect: 40% ZEVs/PHEVs starting with model year (MY) 2026, 100% starting in 2027, and by model year 2028 at the latest, all vehicles must comply with the standard.

While OBD historically served to monitor emission-related components, the perspective changes fundamentally in ZEVs. Battery-electric vehicles and fuel cell vehicles do not have traditional exhaust systems, but instead feature a multitude of components that ensure efficient and safe operation. Their condition directly influences range, aging, and operating costs. ZEVonUDS reflects this shift.

OBDonUDS (SAE J1979-2) refers to components whose failure has a direct impact on a vehicle’s pollutant emissions. The focus is on lambda sensors, catalytic converters, exhaust gas recirculation, particulate filters, and fuel tank venting systems.

ZEVonUDS (SAE J1979-3) refers to components whose failure has a direct impact on the ZEV powertrain. This includes the ZEV powertrain itself, as well as energy storage systems, high-voltage charging systems related to regenerative braking, and thermal management systems that support the powertrain.

Softing Automotive Electronics' offer:

• Comprehensive OBD support
• Flexible configuration options
• Expandable tool architecture
• Support throughout the entire vehicle lifecycle
• From the Softing DTS.monaco development tester to the Softing TDX after-sales tester
• End-to-end customer support across development, diagnostics, and after-sales operations

Illustrative Example: Softing DTS.monaco User Interface

ZEV-relevant drive parameters (PIDs) can be read out with just a few clicks. Error codes (DTCs) and InfoTypes can also be determined and displayed in a central report.

ZEVonUDS allows you to read the state of health of the high-voltage traction battery. That is the ratio of the current capacity to the nominal capacity when new (in percent). Here is an example of reading the Battery Pack State of Health:

Request (functional or physical addressing):

0x22 F4 B2

(0x22 = service identifier; 0xF4 B2 = data identifier)

Response (positive):

0x62 F4 B2 FE

Interpretation: 0xFE = 99.6% SoH

Such values are crucial for warranty decisions, residual value models, and the assessment of battery lifespan.