Clean Truck Check Knowledge Hub
Everything California fleets and diesel RV owners need to understand CARB's Clean Truck Check (HD I/M) program — written in plain English.
What Is Clean Truck Check?
A plain-English breakdown of California's CARB Clean Truck Check (HD I/M) program — who it covers and how it works.
Read guideCARB Requirements (2026 Guide)
Which heavy-duty diesel vehicles must comply in 2026, how often you test, and what each inspection includes.
Read guideWhat Happens If You Fail?
Failed your Clean Truck Check? The most common causes, how to fix them, and how to get compliant fast.
Read guideClean Truck Check vs Smog Check
Why heavy-duty diesels follow a different program than a passenger smog check — and which test your engine needs.
Read guidePenalties in California
What non-compliance costs California fleets — DMV registration holds, daily fines, and CARB enforcement.
Read guideHow to Register in CTC-VIS
A step-by-step walkthrough of registering your fleet in the CTC-VIS database and paying your compliance fee.
Read guideLooking for the official program overview? See our CARB Compliance Guide or view mobile testing pricing.
Need a Test? We Come to You.
Skip the testing station. Our certified technicians perform your Clean Truck Check at your yard, depot, or driveway across Southern California.