Clean Truck Check

Clean Truck Check is California’s heavy-duty inspection and maintenance (HD I/M) program, administered by the California Air Resources Board (CARB). It is designed to ensure most non-gasoline heavy-duty vehicles operating in California keep their emissions-control systems working properly over the life of the vehicle.

The program generally applies to most heavy-duty vehicles with a gross vehicle weight rating above the program threshold operating in California — including out-of-state vehicles that drive into the state. Specific exemptions and phase-in dates apply.

Credentialed testers perform periodic compliance tests using approved methods. Depending on the vehicle, that can include:

• OBD testing. On-board diagnostics checks for vehicles equipped with compliant OBD systems.
• Non-OBD testing. Opacity / smoke testing methods for vehicles without applicable OBD.
• Mobile service. Many testers travel to your yard or facility to test on-site.
• Motor home capability. Some testers are equipped to test motor homes.

We compile publicly posted tester listings into a fast, map-based finder so you can locate a tester near you by ZIP code or city, compare capabilities, and contact them directly. We don’t schedule tests or process compliance — we just help you find a tester.