Short answer: Two things change in 2027. First, the CARB annual compliance fee rises to $33.12 per vehicle for compliance deadlines on and after January 1, 2027 (it is $32.13 in 2026). Second, beginning October 2027, trucks with onboard diagnostics (OBD: diesel model year 2013 and newer, alternative fuel 2018 and newer) must pass a Clean Truck Check test four times a year instead of twice. Older non-OBD diesels stay on the twice-a-year smoke opacity schedule, and California-registered motorhomes and agricultural vehicles stay at once a year.
Some websites say quarterly testing starts January 1, 2027. CARB's FAQ and the regulation (13 CCR § 2196.1(d)) say October 2027.
2027 at a glance
| Date | What changes | Who it affects |
|---|---|---|
| January 1, 2027 | Annual compliance fee becomes $33.12 per vehicle | Every vehicle whose first 2027 deadline falls on or after January 1, 2027 |
| All of 2027 until October | Testing stays twice a year, tied to your DMV registration date (or VIN for non-California plates) | Most trucks |
| October 2027 | OBD-equipped trucks move to four tests a year | Diesel MY2013+ and alternative fuel MY2018+ |
| After October 2027 | Non-OBD trucks keep two tests a year (smoke opacity plus visual) | Diesel MY2012 and older |
| No change | Once a year | California-registered (non-commercial) motorhomes, agricultural vehicles |
The 2027 fee: $33.12 per vehicle
CARB adjusts the fee every year for inflation and must publish the new amount by July 1. The history so far:
| Compliance year | Fee per vehicle |
|---|---|
| 2023–2024 | $30.00 |
| 2025 | $31.18 |
| 2026 | $32.13 |
| 2027 | $33.12 |
The fee is due at the vehicle's first compliance deadline of the year and is paid only in CTC-VIS, by card or TeleCheck eCheck. It is separate from what the tester charges. A fleet of 10 trucks pays $331.20 in CARB fees for 2027. See how much Clean Truck Check costs.
Quarterly testing from October 2027
The regulation sets quarterly deadlines three years after periodic testing took effect (October 1, 2024), which is why the start date is October 2027. In practice:
- Twice as many tests per OBD truck. At published prices of $50–$135 per OBD test, test costs per truck roughly double for the year after the switch.
- The 90-day window still applies. You may test up to 90 days before each deadline. With deadlines every three months, most fleets will be testing almost continuously.
- Telematics helps. Some telematics devices (Geotab, Samsara, Motive, Zonar, Pacific Track, Verizon Connect) are CARB-certified OBD test devices. When a credentialed tester's telematics device is connected, OBD results upload automatically.
- Mobile testing saves the most time. A mobile tester can test a whole yard in one visit. 2,543 of the 2,867 testing businesses we list in California offer mobile testing. Find mobile testers.
Your exact quarterly dates will appear in your CTC-VIS account. CARB has not changed how deadlines are anchored: the DMV registration expiration date for California plates, the last digit of the VIN for other vehicles.
What did not change
- No low-mileage exemption. SB 1064, which would have allowed once-a-year testing for trucks under 1,000 miles a year, was vetoed in September 2026.
- Out-of-state trucks are still covered. CARB says Clean Truck Check applies to all vehicles operating on California roads, despite EPA's January 2026 partial disapproval. See out-of-state trucks.
- Penalties are the same. DMV registration holds and civil penalties of up to $10,000 per day per vehicle under state law. See fines and penalties.
How to get ready for 2027
- Log in to CTC-VIS and check that every vehicle, plate and VIN is current (changes must be reported within 30 days).
- Budget the $33.12 fee per vehicle and pay early in the year so certificates are not delayed.
- Sort your trucks by test type: OBD trucks will need four tests a year from October 2027, older diesels still need smoke opacity testers.
- Line up a tester before peak months. Ask about fleet pricing for recurring visits, or get quotes from up to 3 testers.
- Set up free deadline reminders so no truck misses a window.
Sources
- CARB, Clean Truck Check FAQ
- CARB, Annual vehicle compliance fee update for 2027
- CARB, Requirements for vehicles subject to semi-annual compliance
- 13 CCR § 2196.1, compliance deadlines
- California Assembly Transportation Committee, SB 1064 analysis
- CARB, CARB-certified OBD test devices
Frequently asked questions
Does Clean Truck Check go to 4 times a year in 2027?
Yes, but from October 2027, not January. CARB says OBD-equipped trucks (diesel 2013 and newer, alternative fuel 2018 and newer) will test four times a year beginning October 2027. Older non-OBD trucks stay at twice a year.
What is the Clean Truck Check fee for 2027?
$33.12 per vehicle, for compliance deadlines on and after January 1, 2027. The 2026 fee is $32.13.
Will my motorhome need quarterly testing in 2027?
No. California-registered motorhomes (not used commercially) and agricultural vehicles keep an annual deadline.
Is there a low-mileage exemption in 2027?
No. SB 1064, which proposed once-a-year testing for trucks driven under 1,000 miles a year, was vetoed in September 2026.
CTC Finder is an independent directory and is not affiliated with CARB. Rules change; check CARB's Clean Truck Check pages for the official version.