Amid an EV industry that has no current universal diagnostic standard for electric vehicles, California lawmakers are advancing an EV diagnostics system standard as an element of the Golden State’s Advanced Clean Cars II regulations.
Set to take effect in 2026, the provisions of the Advanced Clean Cars II rules could be adopted by other states, leading to automakers making the EV diagnostic systems in their vehicles compatible with the new universal protocol, Automotive News reports.
The new system will closely resemble the OBD-II (Onboard Diagnostics second generation) diagnostic system already used for ICE vehicles, but adapted for battery-electric requirements. Vehicle makers will need to incorporate diagnostic monitoring in new electric vehicles, which was not even required up to this point because of the machines’ lack of tailpipe emissions.
Additionally, the monitoring systems will need to collect and report the data in a standardized format that will make it accessible using a generic diagnostic scanner. The connector used in EV models, like those equipped in ICE vehicles since 1994, will also need to be accessible to existing diagnostic scan tools. The same regulations will also apply to hydrogen fuel cell vehicles and plug-in hybrids.
The new diagnostic regulations may be adopted by all 17 states currently using California’s emissions rules. Seven of these states have already said they will implement Advanced Clean Cars II rules, which will include the new diagnostics requirements.
The article cites the example of a Chevy Bolt EV which has died twice and gone into “limp mode” with reduced speed and functions on two other occasions. In every case, the Chevrolet dealership was unable to determine the exact cause because the vehicle was not designed to provide diagnostic data for service technicians, leading to three complete replacements of the EV’s battery.
GM now says it will seek “to provide a common experience across vehicle types and service communication tools” and treat EV diagnostics the same way it handles ICE diagnostics systems. The automaker added that its electric vehicle diagnostics will “make it easy for customers to understand potential issues and resolve them at both GM dealers and independent repair facilities.”
Several smaller carmakers, notably Rivian and Lucid, claim to already have some standardized diagnostics in place. Rivian said in a statement that it is “working to ensure we meet these standards as part of our vision to facilitate right-to-repair.”