Program Information
What is a CARB Clean Truck Check?
It's a heavy-duty vehicle inspection and maintenance (HD I/M) regulation to ensure that vehicles’ emissions control systems are properly functioning.
What vehicles are affected by Clean Truck Check?
Clean Truck Check applies to nearly all diesel and alternative fuel heavy-duty vehicles with a gross vehicle weight rating over 14,000 lbs that operate on California public roads & highways even if they are not registered in California.
How often is a Clean Truck Check Required?
Almost all vehicles are subject to semi-annual testing.
Agricultural vehicles (that meet the definition) and California-registered motorhomes for recreational use or emergency occupancy will only be required to undergo testing once per year.
Beginning October 2027, on-board diagnostics (OBD) equipped vehicles will be required to undergo testing four times per year.