California Air Resources Board

Credentialed HD I/M Testers List

The following list is provided as a courtesy for vehicle owners who need to hire the services of a credentialed HD I/M tester to perform compliance testing on their vehicles. Inclusion on this list does not represent an endorsement by CARB. HD I/M compliance testing must be performed by a credentialed HD I/M tester. Individuals on this list have taken CARB’s online HD I/M Tester Training Course and passed the accompanying exam authorizing them to perform on-board diagnostic, smoke opacity, and visual inspections on vehicles subject to the HD I/M regulation. They have also granted CARB staff permission to include them on this courtesy public list.

HD I/M testers’ contact information has been sorted by ZIP Code to assist vehicle owners in locating a HD I/M tester in their area. Testers that have acquired a CARB-verified OBD testing device are identified with a "Yes" in the “OBD Testing Capability” column of the table. CARB will update this list periodically to ensure it is up to date. If you are a credentialed HD I/M tester and wish to update your contact information, or be added to or removed from this list, please email CARB at: hdim@arb.ca.gov.

For individuals wishing to become a HD I/M tester, you may access the HD I/M Tester Training Course at: https://ww2.arb.ca.gov/our-work/programs/inspection-and-maintenance-program/hd-im-tester-training-course-and-exam. To ensure your contact information gets included on this list after you complete the training course, check the “Credentialed HD I/M Tester List” box while registering for the course.

For more information on the requirements of the HD I/M regulation, please visit CARB’s website. You may access the webpage at: https://ww2.arb.ca.gov/our-work/programs/heavy-duty-inspection-and-maintenance-program.

List Date: Current as of March 23, 2023