California Air Resources Board

Latest Office of Administrative Law (OAL)-Approved Heavy-Duty OBD (HD OBD) Regulations

For the latest official versions of the HD OBD and associated enforcement regulations (sections 1971.1 and 1971.5, title 13, California Code of Regulations (CCR)), please see the Barclays Official California Code of Regulations at www.oal.ca.gov .  

2023 Heavy-Duty Engine and Vehicle Omnibus Regulation and Associated Amendments (Board Hearing Date: October 20, 2023)

CARB recently updated the HD Omnibus Rulemaking regulations (first adopted with a Board hearing in August 2020) to address several issues. The rulemaking package includes amendments to the HD OBD regulations to address the application of the OBD requirements for heavy-duty diesel "legacy" engines and engines rated at or greater than 525 bhp maximum power. 

Please visit the official CARB regulatory website for the regulatory documents for this rulemaking.

2021 OBD II and Heavy-Duty OBD (HD OBD) Regulatory Documents (Board Hearing: July 22, 2021)

Amendments to the OBD II and HD OBD regulations (sections 1968.2, 1968.5, 1971.1, and 1971.5 of title 13, CCR) for adoption. You can find the regulatory documents pertaining to the Board Hearing on the OBD II Regulations and Rulemaking website or the official CARB regulatory website.

2020 Heavy-Duty Engine and Vehicle Omnibus Regulation and Associated Amendments (Board Hearing Date: August 27, 2020)

CARB's HD Omnibus Rulemaking would comprehensively overhaul exhaust emission standards and test procedures and other emission-related requirements for 2024 and subsequent model year California-certified HD engines. The rulemaking package includes amendments to the HD OBD regulation to address the proposed new emission standards. 

Please visit the official CARB regulatory website for the regulatory documents for this rulemaking.

2018 HD OBD and OBD II Regulatory Documents (Board Hearing Date: November 15-16, 2018)

Final Statement of Reasons Package 

Here you will find the documents that are part of the final rulemaking package submitted to OAL on August 21, 2019.  OAL approved the rulemaking and filed with the Secretary of State on October 3, 2019, with the rulemaking becoming effective the same day.

• Errata from OAL to Secretary of State: Letter from OAL correcting an error in the final regulation order for section 1968.2, title 13, CCR. 
• Final Statement of Reasons:  Summary of the adopted regulations and each objection and recommendation made by the public during the 45-Day and 15-Day comment periods.  
• Final Regulation Orders: These documents include the strikeout/underline format to identify changes from the current regulations.  The final regulation orders for sections 1971.5 and 1968.2 only include excerpts of the regulations where the changes were made.  
  • Section 1971.1 of Title 13, CCR 
  • Section 1971.5 of Title 13, CCR 
  • Section 1968.2 of Title 13, CCR 
• Executive Order: Used when the Board approved the regulations with the 15-Day changes. 
• Updated Informative Digest: Summary of the regulations and the rulemaking process. 
• Request for Early Effective Date
• Notice of Exemption

Documents for the Second OBD 15-Day Notice: July 19, 2019 

• Second Notice of Public Availability of Modified Text: The Second 15-Day Notice summarizing the changes to the regulations.  The notice includes a summary of the Board's action, a list of the additional changes made to the original proposed amendments to the regulations, availability information of the attachments, and relevant dates. 
• Attachment A: Modified Text of Section 1971.1 of Title 13, CCR: This document includes the bold italic double strikeout/underline format to identify additional changes to the original proposed amendments to the HD OBD regulation made available to the public prior to the Board Hearing.
• Attachment B: Modified Text of Section 1968.2 of Title 13, CCR: This document includes the bold italic double strikeout/underline format to identify additional changes to the original proposed amendments to the OBD II regulation made available to the public prior to the Board Hearing. 

Documents for the First OBD 15-Day Notice: June 4, 2019

• Notice of Public Availability of Modified Text: The 15-Day Notice summarizing the changes to the regulations.  The notice includes a summary of the Board's action, a list of the additional changes made to the original proposed amendments to the regulations, availability information of the attachments, and relevant dates. 
• Attachment A: Modified Text of Sections 1971.1 and 1971.5 of Title 13 CCR: This document includes the double strikeout/underline format to identify additional changes to the original proposed amendments to the HD OBD regulations made available to the public prior to the Board Hearing. 
• Attachment B: Modified Text of Section 1968.2 of Title 13, CCR: This document includes the double strikeout/underline format to identify additional changes to the original proposed amendments to the OBD II regulation made available to the public prior to the Board Hearing.  
• Attachment C: Addendum to the Staff Report: Initial Statement of Reasons: This document includes the double strikeout/underline format to identfy additional changes to the Staff Report. 

Documents for the Board Hearing: November 15-16, 2018

• Board Hearing Presentation: CARB board hearing presentation of the proposed changes to the regulations. 
• Public Hearing Notice: Invitation to public and industry to discuss proposed changes to the regulations. This notice includes the date, time, location, and a summary of the issues to be covered during the hearing. 
• Staff Report: Initial Statement of Reasons (ISOR): Descriptions of the proposed amendments to the regulations. 
  • Appendix A: Proposed Regulation Order: Section 1971.1 of Title 13, CCR 
  • Appendix B: Proposed Regulation Order: Section 1971.5 of Title 13, CCR 
  • Appendix C: Proposed Regulation Order: Section 1968.2 of Title 13, CCR 
  • Appendix D: Data Record Reporting for Over-the-Air Reprogrammed Vehicles and Engines 
  • Appendix E: Proposed Greenhouse Gas Parameters 
  • Appendix F: Economic Analysis Support 

Documents for the HD OBD Workshop: November 2, 2017 

• Workshop Notice: Invitation (Mail-Out #ECARS 17-07) to the public and industry to discuss the proposed amendments to the HD OBD regulation. This notice indicates the date (November 2), time, location, and a quick summary of the issues to be covered during the workshop.  
• Workshop Presentation: CARB workshop presentation of the proposed amendments. 

The regulatory documents for this 2018 OBD rulemaking update can also be found on the official CARB regulatory website.