California Clean Truck Check: 2026 Requirements, Deadlines & Testing Guide
Updated November 2026. Clean Truck Check is California’s mandatory emissions inspection program for heavy-duty vehicles — think of it as the Smog Check for big trucks, but with higher stakes: DMV registration holds, fines of up to $10,000 per vehicle per day, and denial of entry to ports and railyards for non-compliant vehicles. This guide covers who must comply, the 2026 testing schedule, and how to avoid the penalties.
Who Must Comply
Clean Truck Check (formally the Heavy-Duty Inspection and Maintenance, or HD I/M, program) applies to nearly all diesel, alternative-fuel, and hybrid vehicles with a gross vehicle weight rating (GVWR) over 14,000 pounds that operate on California public roads — even if the vehicle is registered in another state. That includes:
- Commercial trucks and tractors, including single-vehicle owner-operators
- Transit, shuttle, school buses, and motorcoaches
- Government vehicles (federal, state, and local), including DMV-exempt plates
- Personal-use heavy-duty vehicles and California-registered motorhomes
- Out-of-state registered trucks that haul into California
Gasoline-powered vehicles are not covered by Clean Truck Check — they remain subject to the regular Smog Check program. Find a smog check station near you
The Three Requirements
To be compliant, a vehicle owner must do all three of the following:
- Report the vehicle in CARB’s Clean Truck Check Vehicle Inspection System (CTC-VIS) and keep the information current (updates required within 30 days of buying or selling a vehicle).
- Pay the annual compliance fee per vehicle, inside CTC-VIS only (card or e-check — paper checks and other CARB portals are not accepted). The fee adjusts annually with California CPI; it was $31.18 in 2025.
- Submit passing emissions tests by each compliance deadline, performed and submitted by a CARB-credentialed tester.
2026 Testing Schedule and Deadlines
Most vehicles must test twice per year (semi-annually) in 2026. For California-registered vehicles, compliance deadlines are tied to the DMV registration expiration date, then every six months after. Out-of-state and exempt-plate vehicles get deadlines based on the last digit of the VIN. Your exact dates appear in your CTC-VIS account — those account dates are what CARB enforces.
- Now through September 2027: semi-annual testing (twice per year) for most vehicles.
- Starting October 1, 2027: testing increases to four times per year — but only for OBD-equipped vehicles. Opacity-tested vehicles stay semi-annual.
- Agricultural vehicles and California-registered motorhomes: annual testing only.
The 90-day window: a passing test may be submitted up to 90 days before the deadline. Smart operators test at the start of the window — if the vehicle fails, that leaves time for repairs and a retest before the deadline instead of after it.
OBD Test vs. Smoke Opacity Test — Which One Your Vehicle Needs
| OBD Test | Smoke Opacity + Visual Inspection | |
|---|---|---|
| Applies to | 2013 and newer diesel engines; 2018 and newer alternative-fuel engines | 2012 and older diesel engines (non-OBD) |
| What happens | Electronic scan of the engine’s on-board diagnostics using a CARB-certified device — no active emissions fault codes or MIL (check engine) issues allowed | SAE J1667 smoke opacity measurement plus a visual inspection of emissions control equipment |
| Common gotcha | “Not Ready” result — the vehicle must be driven further to meet OBD readiness criteria, then retested | Missing or tampered emissions components fail the visual inspection regardless of smoke readings |
Check the engine’s emissions control label (ECL) to confirm the engine model year — it’s often one year older than the vehicle model year, and the engine year is what determines the test type.
What Happens If You Don't Comply
- DMV registration holds — the DMV blocks registration renewal for non-compliant vehicles, including DMV-exempt plates. CARB transmits the compliant-VIN list to DMV nightly; allow 1–3 business days after meeting requirements for the hold to clear.
- Fines of up to $10,000 per vehicle per day for continued non-compliance.
- Port and railyard denial — non-compliant vehicles may be refused entry.
- Roadside enforcement — CARB and CHP conduct inspections at weigh stations and roadside, and roadside emissions monitors with license plate readers screen for high emitters statewide. A flagged vehicle receives a Notice to Submit to Testing (NST) and has 30 calendar days to submit a passing test from a credentialed tester.
- Freight contractors and brokers may only dispatch compliant vehicles, so non-compliance can cost you loads, not just fines.
Note for out-of-state carriers: in January 2026 the U.S. EPA issued a partial disapproval of the state plan related to Clean Truck Check, and some coverage has caused confusion — but CARB confirms the program remains in effect for all vehicles operating on California roads, including out-of-state trucks. Don’t skip compliance based on headlines.
Where to Get Tested
Clean Truck Check FAQ
Find Clean Truck Check testers near you: Rowland Heights · Bellflower · South Gate · South Pasadena · Temple City · Hawthorne · Bell Gardens · South Whittier
Does Clean Truck Check apply to pickup trucks?
Only if the GVWR exceeds 14,000 pounds and the vehicle is diesel or alternative-fuel powered. Most consumer pickups (Class 1–3) are under that threshold and remain in the regular Smog Check program.
How often do I need to test in 2026?
Twice per year for most vehicles. Agricultural vehicles and California-registered motorhomes test annually. Starting October 1, 2027, OBD-equipped vehicles move to four tests per year.
My truck is registered in another state. Do I still need to comply?
Yes — Clean Truck Check applies to any subject vehicle operating on California public roads regardless of where it’s registered. Out-of-state vehicles receive compliance deadlines based on the last digit of the VIN.
What does compliance cost?
The annual compliance fee is roughly $31 per vehicle (CPI-adjusted each year), plus the cost of testing by a credentialed tester, which varies by provider and whether it’s an OBD scan or an opacity test.
Can I do the test myself?
Only if you become a CARB-credentialed tester — the training course is free and online, and requires scoring at least 80% on the exam, with the credential renewed every two years. Many single-truck owners use a third-party tester instead.