California Air Resources Board

Where can I find the tester exam?

Tester Training Course, Exam, and Certification

Where do I find my HD I/M Tester Identification Number and what does it look like?

It is in the bottom left corner of your Certificate of Completion issued after taking the HD I/M Tester Training and passing the exam. Your HD I/M Tester Identification Number will have eight characters and start with two capital letters followed by six numerals. The HD I/M Tester Training system will provide you with an electronic version of your Certificate of Completion for downloading and printing immediately after you pass the exam. Retain this for your records.

Does my HD I/M Tester Identification Number ever expire? How do I renew it?

Your unique HD I/M Tester Identification Number is valid for two years from the date you passed the exam. Your Certificate of Completion includes your Tester ID expiration date. To renew your HD I/M Tester Identification Number, you must retake the HD I/M Tester Training Course and pass the exam again.

Can I share my HD I/M Tester Identification Number with co-workers who also want to perform HD I/M compliance testing?

No. Your Identification Number is unique to you and every tester must take the training and pass the exam to obtain their own Identification Number.

What testing equipment do I need to perform HD I/M compliance tests?

To perform smoke opacity testing, you will need a SAE J1667-compatible smoke meter. A list of manufacturers and their contact information that sell SAE J1667-compatible smoke meters is available on CARB's website.

To perform the Vehicle Emissions Control Equipment Inspection, you will need access to reliable sources of engine and vehicle technical specifications, such as service and repair manuals. The standard form for completing and submitting results to CARB is available at Vehicle Emissions Control Equipment Inspection Form.

To perform OBD compliance tests, a HD I/M tester must use a CARB-validated OBD test device. A list of manufacturers with CARB-validated OBD test devices is available on CARB’s website at: OBD Test Devices. Please ensure you have read and understand the OBD Readiness Criteria and Test Results FAQ.

CARB’s webpage will continually be updated as devices become approved for use in the program.

What if I already have a smoke meter or an OBD scan tool – can I use those?

If you already have a SAE J1667-compatible smoke meter, you may continue to use that for HD I/M compliance testing on vehicles without OBD systems. While there are existing OBD scan tools already on the market, you can only use one that has been validated by CARB for use in the HD I/M program and is on CARB’s list of OBD Test Devices: SAE J1667-Compatible Smoke Meters.

Attempting to use an OBD test device that is not validated by CARB will result in an unsuccessful test on the vehicle on which it is used. I have a valid smoke tester certification from the California Council on Diesel Education and Technology (CCDET).

Do I still have to take CARB’s HD I/M Tester Training Course?

Yes. To perform HD I/M compliance testing starting in January 2023, you must take the HD I/M Tester Training and pass the exam. Smoke tester identification numbers obtained through CCDET for the Periodic Smoke Inspection Program (PSIP) are not valid for performing vehicle compliance tests within the HD I/M program.

How and when will I be able to find HD I/M testers in my area to hire for HD I/M compliance testing for my vehicles?

You may find available for hire testers at Credentialed Testers List.

Inclusion on this list is not an endorsement by CARB but merely a courtesy for HD I/M testers and vehicle owners that may need their services.

Why am I not on the public list of HD I/M testers?

If you want to be on the public list of HD I/M testers that offer for-hire testing services, please send an email to hdim@arb.ca.gov with your contact information (name, business name, email, phone number) and a copy of your HD I/M Tester Training Certificate of Completion and request to be added to the list. We will update the list periodically and your contact information will appear on the next update. My information on the public list of HD I/M testers is incorrect.

How do I update my information on the public tester list?

Please send an email to hdim@arb.ca.gov with the contact information as it currently appears on the list, your HD I/M Tester Identification Number, and the information that you are requesting to be corrected. We will update the list periodically and your modified contact information will appear on the next update.

I am on the public HD I/M tester list but want to be removed. What do I do?

Please send an email to hdim@arb.ca.gov with your contact information and your HD I/M Tester Identification Number and request to be removed from the list. We will update the list periodically and your contact information will be removed on the next update.

Where do I get additional information on the HD I/M program?

For more information, visit Clean Truck Check (HD I/M).

You may also view CARB’s training modules developed for the HD I/M Tester Training Course at Reference Videos for Credentialed Testers. Scroll to the Helpful Videos section to view them. These modules provide more in-depth information on the requirements of the HD I/M regulation and testing procedures.

How can I receive updates on HD I/M program activities?

To receive automatic email updates on HD I/M program activities, such as when additional CARB-validated OBD test devices are available for use in the HD I/M program, sign up on the GovDelivery list at California Air Resources Board (govdelivery.com).

Where can I find the text of the final HD I/M regulation?

The HD I/M regulation, referred to as the final regulation order, is in title 13, California Code of Regulations, sections 2195 - 2199.1 and is available at Final Regulation Order - Attachment A-1 Heavy-Duty Inspection and Maintenance Program.

If I have additional questions, how do I contact CARB?

Please email staff at hdim@arb.ca.gov. We generally respond within one to three business days.