If you operate a diesel truck or heavy-duty vehicle in California, you’ve probably heard of the CARB Clean Truck Check program. But hearing about it and actually passing it are two very different things. This guide will walk you through how to get a Clean Truck Check certificate in California, including what’s required, where to test, and how to stay compliant.
Whether you're managing a fleet or driving solo, here’s what you need to know to pass and prove it.
What Is a Clean Truck Check Certificate?
A Clean Truck Check certificate verifies that your vehicle has passed California’s required emissions inspection under the CARB HD I/M program. It confirms that your truck meets current emission standards and is compliant for registration and operation in the state.
Testing and certification is mandatory for:
- Diesel and alternative fuel vehicles over 14,000 lbs GVWR
- Both in-state and out-of-state vehicles operating on California roads
- Trucks with 2013+ model year engines (OBD-equipped) and older heavy-duty diesel vehicles
Step-by-Step: How to Get Certified
1. Register Your Vehicle
Before you can test, your vehicle must be registered in the CTC-VIS (Clean Truck Check – Vehicle Inspection System).
You’ll need to create an account, add your vehicle(s), and pay the $30 annual compliance fee per vehicle.
Learn how to register for your vehicle in the CTC-VIS here: How to Register Your Vehicle with Clean Truck Check.
2. Choose the Right Emissions Test
The type of test you need depends on your vehicle’s age and engine type:
- OBD Test: For most diesel vehicles with 2013 and newer engines, a plug-in On-Board Diagnostics test is required.
- Opacity Test: For older trucks, a traditional Smoke Opacity Test may still be necessary.
Your tester will determine the right test based on your VIN and engine model.
3. Find a CARB-Credentialed Tester
Only certified providers can perform the Clean Truck Check and submit your results. Look for testers who are:
- CARB-credentialed
- Able to submit results directly to the CTC-VIS system
- Offering mobile service (like FleetFox) or fixed-site appointments
Avoid unverified shops that cannot submit results—you’ll waste time and fail to meet compliance.
4. Complete the Test
Your truck will undergo an inspection based on its engine model year:
- OBD test: Tester plugs into your vehicle and checks the emissions system for faults, trouble codes, and system readiness.
- Opacity test: Visual and mechanical inspection followed by tailpipe testing using a smoke meter.
Each test usually takes 10–20 minutes per vehicle.
5. Receive Your Certificate
Once your truck passes the test:
- The provider uploads your results to CTC-VIS
- Your compliance status is updated automatically
- You may download or print your Clean Truck Check certificate from your online account
- DMV registration holds will be cleared within a short period
How Often Do You Need to Test?
Currently:
- Most vehicles must test twice per year
- By October 2027, trucks with OBD systems will be required to test quarterly
Your test schedule is tied to your last digit of the VIN and posted deadlines in your CTC-VIS dashboard.
Final Tips for Passing the Clean Truck Check
- Fix any check engine lights before testing
- Stay on schedule—late tests can result in registration holds or fines
- Don’t wait for a notice—proactive testing keeps your fleet legal and moving
Need a Clean Truck Check Fast?
FleetFox offers certified, mobile Clean Truck Check testing across California. We come to you, perform the test, and upload results directly to CARB—all without taking your vehicle off the road.
