If you own or operate a heavy-duty diesel truck in California, you've probably heard about Clean Truck Check. This guide explains the program in plain terms and — just as important — shows you where to confirm the official requirements for your specific truck.
We're a mobile truck service and CARB-credentialed tester, not a regulator. Rules, deadlines and fees are set by the California Air Resources Board (CARB) and can change, so treat this as an orientation and use CARB's own pages as the final word.
What the Clean Truck Check program is
Clean Truck Check is CARB's heavy-duty inspection and maintenance program. Its purpose is to make sure emissions control systems on heavy-duty vehicles keep working as designed throughout the vehicle's life — and that problems get repaired rather than ignored.
The program covers heavy-duty diesel and other non-gasoline vehicles operating in California. According to CARB, it also applies to vehicles registered outside California when they operate in the state.
What vehicle owners are responsible for
CARB's vehicle owner information describes several responsibilities. In general terms, owners need to:
- Report their vehicles in CARB's Clean Truck Check reporting system (CTC-VIS).
- Pay CARB's annual compliance fee for each vehicle.
- Have periodic emissions tests performed by a CARB-credentialed tester and submitted on time.
- Repair emissions-related problems when a vehicle doesn't pass.
How often and how trucks are tested
Testing frequency and deadlines are set by CARB and depend on your vehicle and CARB's schedule, which has changed as the program has phased in. The test method also depends on the vehicle — newer trucks are generally tested through their on-board diagnostics (OBD) system, while older trucks may use a different procedure.
Because these details matter and can change, check CARB's vehicle owner information for your truck, or call us and we'll help you find the right page. Then book your Clean Truck Check ahead of your deadline.
Staying ahead of your deadlines
A few habits make compliance a lot less stressful:
- Keep a simple calendar of each truck's testing deadlines.
- Schedule testing early enough that there's time to fix a problem if one turns up.
- Don't ignore warning lights — emissions-related faults are exactly what testing is designed to find.
- Pair testing with routine maintenance like an oil change so one visit covers more.
If your truck doesn't pass
A failed test isn't the end of the road — it's a signal that something needs attention. The next step is a proper diagnosis to find the cause, followed by repair and a retest. Read more in What Happens If a Truck Has Problems During Clean Truck Check?
Frequently asked questions
Where do I find the official Clean Truck Check requirements?
On CARB's Clean Truck Check program pages, including the vehicle owner information page. Links are listed in the sources section of this article.
Does a Clean Truck Check replace my regular maintenance?
No. Testing checks emissions-related systems at a point in time. Regular maintenance like oil changes and inspections still matters for keeping the truck reliable.