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The California Air Resources Board (CARB or Board) will conduct a public hearing at the date and time noted below to consider approving for adoption the proposed amendments to California’s On-Board Diagnostic System Requirements for Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines (OBD II) and Heavy-Duty Engine On-Board Diagnostic System Requirements (HD OBD).

Date:                 July 22, 2021
Time:                 9:00 a.m.

Please see the public agenda which will be posted ten days before the July 22, 2021, Board Meeting for any appropriate direction regarding a possible remote-only Board Meeting. If the meeting is to be held in person, it will be held at the California Air Resources Board, Byron Sher Auditorium, 1001 I Street, Sacramento, California 95814.

This item will be considered at a meeting of the Board, which will commence at
9:00 a.m., July 22, 2021, and may continue at 8:30 a.m., on July 23, 2021. Please consult the agenda for the hearing, which will be available at least ten days before July 22, 2021, to determine the day on which this item will be considered.



CARB staff is proposing amendments to the on-board diagnostics II (OBD II) regulation (title 13, California Code of Regulations (CCR), section 1968.2), the heavy-duty OBD (HD OBD) regulation (title 13, CCR, section 1971.1), and the OBD II and HD OBD enforcement regulations (title 13, CCR sections 1968.5 and 1971.5, respectively). Since the regulations were last amended in 2018, CARB staff has identified a number of new amendments to the regulations that staff believes are warranted to address issues with the OBD regulations, in-use issues with the OBD systems, and manufacturers’ concerns with specific requirements. The proposed amendments include requiring OBD systems to store more information regarding emission-related malfunctions and in-use monitor performance, adding details about the specific supporting data required for diesel catalyst/adsorber and oxides of nitrogen sensor monitors, modifying the cold start emission reduction strategy monitoring requirements, and revising the particulate matter filter monitoring requirements.

Inquiries concerning the substance of the proposed regulatory action may be directed to the agency representative Jason Wong, Manager, On-Board Diagnostics Program Development Section, at (626) 575-6838 or Jason.Wong@arb.ca.gov, or Adriane Chiu, Air Resources Engineer, On-Board Diagnostics Program Development Section, at (626) 350-6453 or Adriane.Chiu@arb.ca.gov. If you are unable to reach the preceding designated contacts, please contact Chris Hopkins, Regulations Coordinator, at Chris.Hopkins@arb.ca.gov or (916) 445-9564.


Notice of Public Hearing

The Notice, ISOR, and all subsequent regulatory documents are available on CARB’s Rulemaking webpage.


Written Comment Period & Comment Submittal

In accordance with the Administrative Procedure Act, interested members of the public may present comments orally or in writing during the hearing and may provide comments by postal mail or by electronic submittal before the hearing. The public comment period for this regulatory action will begin on June 4, 2021. Written comments not submitted during the hearing must be submitted on or after June 4, 2021, and received no later than July 19, 2021. Comments submitted outside that comment period are considered untimely. CARB may, but is not required to, respond to untimely comments, including those raising significant environmental issues. CARB requests that when possible, written and email statements be filed at least ten days before the hearing to give CARB staff and Board members additional time to consider each comment. The Board also encourages members of the public to bring to the attention of staff in advance of the hearing any suggestions for modification of the proposed regulatory action. Comments submitted in advance of the hearing must be addressed to one of the following:

Clerks’ Office, California Air Resources Board
1001 I Street, Sacramento, California 95814


Electronic Submittal

Please note that under the California Public Records Act (Government Code section 6250 et seq.), your written and oral comments, attachments, and associated contact information (e.g., your address, phone, email, etc.) become part of the public record and can be released to the public upon request.