The California Air Resources Board (CARB) requires certain heavy-duty diesel vehicles to undergo Clean Truck Check inspections to ensure emissions compliance. Here's what your fleet needs to know to stay compliant in 2026.
Vehicles Required to Comply
Clean Truck Check applies to:
- Heavy-duty diesel vehicles over 14,000 lbs GVWR
- Commercial fleet trucks operating in California
- Vehicles registered in or entering California regularly
- Diesel motorhomes and RVs above the weight threshold
- Agricultural and public agency vehicles
New to the program? Start with what Clean Truck Check is.
What the Inspection Includes
Depending on the vehicle, testing may include:
- On-board diagnostics (OBD) checks
- Emissions system verification
- Engine fault code scanning
- Visual inspection of emissions components
Which test you need depends on your engine's model year — see Clean Truck Check vs smog check.
Compliance Frequency
Testing frequency may vary depending on:
- Vehicle type
- Usage patterns
- CARB requirements updates
Commercial Trucks
Semi-Annual
Testing is required twice per year for most commercial operations.
RVs & Ag Vehicles
Annual
Testing is required once per year for diesel motorhomes and ag vehicles.
Fleet managers should monitor CARB updates regularly to stay compliant, since deadlines are tied to each vehicle's DMV registration date.
Penalties for Non-Compliance
Failing to comply with Clean Truck Check requirements can result in:
- Fines and penalties
- Vehicle registration issues
- Fleet operational restrictions
- Possible enforcement actions by CARB
Get the full picture in our penalties and fines guide.
Staying Compliant
The easiest way to stay compliant is to schedule regular inspections with a certified Clean Truck Check provider, especially for fleets operating across multiple regions in California. Explore our mobile testing services, read the full CARB compliance guide, or check pricing and book a check for your fleet.