CARB HD I/M · Updated November 2026
Clean Truck Check (CARB HD I/M): Complete 2026 Compliance Guide
Who has to comply, when your truck is due, what test it needs, what it costs, and the easiest ways to stay compliant, whether you run one truck or a whole fleet.
At a glance
- Who
- Diesel and alternative-fuel vehicles over 14,000 lbs GVWR operating in California
- How often
- Twice a year. OBD-equipped trucks go to four times a year starting October 2027
- CARB annual fee
- $32.13 per vehicle in 2026, $33.12 from January 1, 2027
- Early testing
- Passing tests count up to 90 days before your deadline
- Test type
- OBD test for 2013 and newer diesel engines. Smoke opacity and visual inspection for 2012 and older
The basics
What is Clean Truck Check?
Clean Truck Check is the California Air Resources Board’s Heavy-Duty Inspection and Maintenance program (HD I/M). It replaced the old periodic smoke inspection program with an ongoing system tied to each vehicle’s VIN and registration. Every covered vehicle has three jobs.
Report the vehicle
Add each truck to your account in CARB’s Clean Truck Check system (CTC-VIS).
Pay the annual fee
One compliance fee per vehicle per year, paid to CARB.
Pass periodic testing
Submit a passing emissions test before each deadline, through a CARB-credentialed tester or a CARB-certified device like AIRPASS™.
Who it applies to
Who has to comply?
Nearly every non-gasoline vehicle over 14,000 lbs GVWR that operates in California, including trucks registered in other states.
California-registered trucks
Compliance is tied to your DMV registration. If a truck isn’t compliant, DMV can hold the registration renewal.
Out-of-state trucks
If the truck runs in California, CARB says Clean Truck Check applies wherever it’s plated, and enforcement happens at roadside and border inspections.
In early 2026 the EPA approved the program only for California-registered vehicles. CARB says it will keep enforcing it for every truck. What that means for you →
What isn’t covered
Gasoline vehicles, and vehicles at or under 14,000 lbs GVWR. A few specialty categories have their own rules, so check CARB’s list if you run something unusual.
Deadlines
When is your truck due?
Your exact deadlines show in your CTC-VIS account. Here’s how CARB sets them.
-
California-registered: your registration month
The first deadline follows your DMV registration expiration, then every six months after.
-
Out-of-state and DMV-exempt: your VIN
Deadlines are set by the last digit of the VIN, twice a year.
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Test up to 90 days early
A passing test submitted in the 90 days before a deadline counts. Testing early leaves time to fix and retest if something fails.
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Coming October 2027: four tests a year
OBD-equipped trucks move to four tests a year. Non-commercial motorhomes and qualifying agricultural vehicles stay on one test a year.
Test types
What test does your truck need?
It depends on the engine model year, not the truck’s. Check the emissions label on the engine; it’s often a year older than the vehicle.
| Engine | Required test | Your AIRLIMITS options |
|---|---|---|
| Diesel, 2013 and newer | OBD test with a CARB-certified device | AIRPASS™ or a mobile OBD test |
| Alternative fuel, 2018 and newer | OBD test with a CARB-certified device | AIRPASS™ or a mobile OBD test |
| Diesel, 2012 and older | Smoke opacity test plus emissions control equipment inspection | Mobile opacity test (OVI) |
| Alternative fuel, 2017 and older | Emissions control equipment inspection only | Mobile inspection |
| Off-road engine in an on-road vehicle | Smoke opacity test plus inspection, any model year | Mobile opacity test (OVI) |
Cost
How much does Clean Truck Check cost?
There are two separate costs: CARB’s annual fee, and the testing itself.
Paid to CARB
per vehicle, per year (2026)
Rises to $33.12 on January 1, 2027. CARB adjusts it each year.
AIRPASS™ · automatic
per truck · no setup fee · cancel anytime
Unlimited tests, including when testing goes to four times a year.
Mobile testing · we come to you
$325 per smoke opacity (OVI) test
Fleet rates available. A credentialed tester comes to your yard or job site.
Don’t want to touch your CARB account at all? The Zero CARB Plan has us manage it, pay your annual CARB fee and send your certificates where they need to go. Ask about Zero CARB →
Step by step
How to comply in four steps
Create your CTC-VIS account
Sign up on CARB’s Clean Truck Check portal. Your vehicles, fees, results and certificates all live there.
Add your vehicles
Enter each truck’s VIN, plate and engine details.
Pay the annual fee
$32.13 per vehicle for 2026, paid to CARB in the portal.
Test before every deadline
This is the step people miss. AIRPASS™ handles it automatically, or book a mobile test.
Your options
AIRPASS™ or mobile testing?
| AIRPASS™ | Mobile testing | |
|---|---|---|
| Best for | 2013 and newer diesel trucks | Older trucks, one-off tests and mixed fleets |
| How the test happens | Plugs into the diagnostic port, runs the test and submits it to CARB | A credentialed tester comes to you and submits the result |
| Price | $25 / month per truck, unlimited tests | $175 per OBD test · $325 per opacity test |
| Downtime | None. Keep driving | A short stop at your yard or job site |
| Four tests a year (Oct 2027) | Same monthly price | Four visits a year per truck |
| Get AIRPASS™ → | Book a mobile test → |
When things go wrong
If a truck fails or misses a deadline
If the test fails
The result shows what needs repair. Fix it and test again. Common causes: active emissions fault codes, an incomplete drive cycle, DPF or SCR faults, and missing or modified emissions equipment.
With AIRPASS™, tests are unlimited while your plan is active. How to complete a drive cycle →
If you miss a deadline
- California-registered trucks can get a DMV registration hold
- CARB can issue penalties
- Out-of-state trucks can be stopped at roadside and border inspections
- The next deadline doesn’t move
Clean Truck Check with AIRLIMITS
Your team for CARB compliance
We’ve handled emissions testing and compliance since 2014, as CARB-credentialed HD I/M testers based in Long Beach. Beyond testing, we help with Notices to Submit, registration holds and CTC-VIS record problems.
- AIRPASS™ for automatic testing, anywhere you drive
- Mobile OBD and smoke opacity testing
- Zero CARB Plan: we manage your CARB account for you
- Call or text 1-800-788-5241, any time
17 reviews on Google
“No more need to schedule someone to come and do the clean truck check, the truck automatically does it and sends the results in with their device.”
Andrew Wedlock · Google review
How often do I need to test?
Twice a year for most trucks today. Starting October 2027, OBD-equipped trucks test four times a year. Non-commercial motorhomes and qualifying agricultural vehicles test once a year.
Do out-of-state trucks need Clean Truck Check?
According to CARB, yes. If the truck operates in California, Clean Truck Check applies no matter where it’s registered. In early 2026 the EPA approved the program only for California-registered vehicles, but CARB says it continues to enforce it for all trucks, including at roadside and border inspections.
How much is the CARB fee?
$32.13 per vehicle for 2026, rising to $33.12 on January 1, 2027. It’s paid to CARB in your CTC-VIS account and is separate from the cost of testing.
What test does my truck need?
2013 and newer diesel engines and 2018 and newer alternative-fuel engines need an OBD test with a CARB-certified device. 2012 and older diesel engines need a smoke opacity test plus an emissions control equipment inspection. 2017 and older alternative-fuel engines need the inspection only.
Is AIRPASS™ approved by CARB?
Yes. AIRPASS™ is a CARB-certified continuously connected device, Executive Order IM-006-0001-4, for OBD-equipped trucks. It runs the test and submits it to CARB.
Can I test early?
Yes. A passing test submitted up to 90 days before a deadline counts toward that deadline.
What happens if my truck fails?
The result shows what needs repair. Fix it and test again before your deadline. With AIRPASS™, tests are unlimited while your plan is active.
Where do I get my certificate?
In your CTC-VIS account on CARB’s Clean Truck Check portal. On the Zero CARB Plan, we download your certificates and send them where they need to go.
Stay compliant without the hassle.
Get AIRPASS™ for $25 a month per truck, or have a credentialed tester come to you.
Sources: CARB Clean Truck Check testing requirements and 2027 compliance fee update. CARB makes the final determination on all regulatory matters.