California’s Clean Truck Check Program: Your Guide to Compliance

David Briscoe
Oct 31
5 min read

Updated: 2 days ago

California’s Clean Truck Check program is transforming how diesel and heavy-duty vehicle owners maintain compliance with emissions laws. If you operate a diesel truck, trailer, or fleet in the state — or even drive in from out of state — you’re part of this new era of accountability.

In a recent webinar hosted by the California Air Resources Board (CARB), program lead Randy Opfer outlined how the system works, what deadlines apply, and how fleets can avoid costly registration holds. Here’s a full breakdown in plain English — plus what you can do to stay compliant with help from Rollin’ VIN Verifiers.

1. What Is the CARB Clean Truck Check Program?

The Clean Truck Check is California’s new emissions inspection program for heavy-duty, non-gasoline vehicles over 14,000 pounds GVWR. It functions much like the smog-check system for passenger cars but is designed for trucks, buses, and other diesel or alternative-fuel vehicles.

The program ensures that each heavy-duty vehicle operating on California roads maintains its factory-installed emission control systems and passes periodic emissions tests. If your vehicle runs on diesel, CNG, LNG, or propane — and it’s not primarily gasoline — it’s subject to Clean Truck Check if it meets the weight threshold. That includes:

Commercial trucks and tractors
Delivery vehicles and Sprinter vans over 14,000 lbs
Buses and tow trucks
Government-owned vehicles
California-registered diesel motorhomes

Even out-of-state vehicles entering California must comply if they meet the criteria.

All participating vehicles must be reported through the Clean Truck Check Vehicle Inspection System (CTC-VIS) — CARB’s official compliance database. Fleet owners are required to:

Create a CTC-VIS account and report each qualifying vehicle.
Pay the annual compliance fee — currently about $31 per vehicle (adjusted yearly for inflation).
Submit passing emissions test results before the test due date.

Once your vehicle information, compliance fee, and test data are aligned in the system, the vehicle is marked as compliant. CARB enforcement officers have live access to this database and use it to verify compliance during roadside inspections or enforcement stops.

For fleet managers, keeping your CTC-VIS account accurate and up-to-date is essential. Add or remove vehicles within 30 days of any change to avoid discrepancies that could lead to warnings or holds.

2. Understanding the Emissions Test Types

The emissions test you need depends on your engine model year and fuel type:

OBD (On-Board Diagnostics) Test – For 2013 and newer diesel engines and 2018 and newer alternative-fuel engines. The tester connects a CARB-approved OBD device to the truck’s diagnostic port and downloads data about emissions system performance.
Opacity Test (Snap Idle / Snap Acceleration) – For 2012 and older diesel engines. A smoke meter measures exhaust opacity during three quick rev cycles while the truck is in neutral.
Visual Inspection – Required for all non-OBD vehicles and certain pre-2018 alternative-fuel trucks to confirm emissions equipment is intact and operational.

CARB-credentialed testers must use CARB-certified testing devices for both OBD and opacity testing. Only results uploaded by credentialed testers are accepted in the CTC-VIS system.

3. How Often Do You Need to Test?

Testing frequency depends on vehicle type:

Most commercial trucks: Twice per year (every six months).
Agricultural vehicles: Once per year.
California-registered diesel motorhomes: Once per year.
OBD-equipped vehicles: Moving toward quarterly testing in future updates.

Each vehicle’s due date is tied to its DMV registration renewal month, with the next test required six months later. CARB allows testing up to 90 days early — a crucial advantage. Testing early gives owners time to repair issues or handle parts delays without risking non-compliance.

4. What Happens if You Fail or Miss a Deadline?

Failing a test doesn’t automatically make you non-compliant — as long as you pass before your deadline. You can retest as many times as needed; only the last passing test counts. However, missing a deadline can trigger enforcement actions, including:

A Notice to Submit to Testing (NST) letter if your vehicle was flagged by roadside sensors as a high emitter.
A registration hold from DMV until you resolve the issue.

If a part is on backorder or your vehicle can’t pass due to repairs, contact CARB early by emailing HDIM@arb.ca.gov with the VIN and explanation. In some cases, fleets may qualify for a temporary 5-day operating pass to complete testing.

5. Testing Equipment, Credentials, and Quality Control

Only CARB-credentialed testers using approved testing devices can perform and upload emissions results. Credentialed testers must complete CARB’s online training course and pass a certification exam with an 80% or higher score. Credentials are valid for two years.

Testers are required to ensure accuracy. Any attempt to falsify data can lead to credential revocation and penalties. For fleet owners, it’s your responsibility to verify your tester’s credentials before testing. You can search for certified testers using CARB’s Credentialed Tester Database or simply choose a trusted service like Rollin’ VIN Verifiers, which employs CARB-approved testers and devices.

6. Why the Program Matters

CARB’s Clean Truck Check program supports California’s mission to reduce emissions from the state’s more than one million heavy-duty vehicles. Diesel exhaust is a major source of nitrogen oxides and particulate matter — pollutants that contribute to smog and health issues.

By ensuring emissions systems stay functional and vehicles remain clean, the program aims to improve air quality, extend vehicle life, and hold all operators — in-state and out-of-state — to the same environmental standard.

7. Common Issues & Solutions

CARB’s Q&A session highlighted several common concerns:

CTC-VIS not updating: The system can lag a few weeks after test uploads or fee payments. CARB is improving this, but always save your receipts and email HDIM@arb.ca.gov if issues persist.
Duplicate or incorrect VINs: Deactivate the incorrect VIN in your account or contact CARB to correct it.
Parts unavailable: Notify CARB early; enforcement is flexible with documented delays.
Low-mileage vehicles: Still must test unless registered as agricultural or personal-use diesel motorhomes.
DMV holds: Call the DMV Field Office Support Unit or show your Clean Truck Check certificate in person to release registration.

8. How Rollin’ VIN Verifiers Can Help

At Rollin’ VIN Verifiers, we simplify compliance for fleets and individual truck owners.

Our services include:

✅ Mobile OBD and Opacity Testing — We come to your yard or business.

✅ Fleet Compliance Management — We track deadlines and send reminders 90/60/30 days out.

✅ CTC-VIS Setup & Portal Assistance — We help report vehicles, pay compliance fees, and verify uploads.

✅ DMV Support — If your registration is held, we help provide documentation to get it cleared quickly.

We work with fleets across Riverside, Fontana, Mira Loma, Ontario, and San Bernardino to keep trucks on the road — clean, compliant, and ready for inspection.

9. Final Thoughts

CARB’s Clean Truck Check program is here to stay — and it’s only expanding. Understanding your reporting requirements, testing schedule, and how to manage CTC-VIS properly can save you time, money, and headaches.

The key takeaway from the CARB webinar?👉 Stay proactive. Test early. Keep your records clean. If you need help with mobile testing, fleet reminders, or portal setup, Rollin’ VIN Verifiers is your trusted CARB-credentialed partner.