Clean Truck Check has two changes coming in 2027. The yearly CARB fee goes up on January 1, and starting October 1, 2027, trucks with OBDII go from two tests a year to four. Here’s what’s changing, what’s staying the same, and how to stay ahead of your dates.

Checked against CARB’s published requirements on November 9, 2026. Every source is linked at the bottom of this page.

2027 Clean Truck Check changes at a glance

January 1, 2027: The yearly compliance fee goes from $32.13 to $33.12 per vehicle.
October 1, 2027: Trucks with OBDII (2013 and newer diesel engines, 2018 and newer alternative fuel engines) move to four tests a year.
January 1, 2027: A temporary exemption for new engines certified to CARB’s optional ultra-low NOx standard ends. CARB notes no manufacturer had certified an engine to that standard as of mid-2024, so most owners won’t notice this one.
Staying the same: Older trucks without OBDII stay at two tests a year. California motorhomes for personal use and agricultural vehicles stay at one test a year.

How often do you test? Before and after October 1, 2027

Vehicle	Test	Now through Sept. 30, 2027	Starting Oct. 1, 2027
Diesel or diesel hybrid, 2013 and newer engine	OBDII scan	2 per year	4 per year
Alternative fuel (like natural gas) or alternative fuel hybrid, 2018 and newer engine	OBDII scan	2 per year	4 per year
Diesel, 2012 and older engine	Smoke opacity test and visual inspection	2 per year	2 per year
Alternative fuel, 2017 and older engine	Visual inspection	2 per year	2 per year
California motorhome (personal or emergency use) or agricultural vehicle	Based on engine year	1 per year	1 per year

Motorhomes used for business follow the regular truck schedule, not the once-a-year schedule.

Change #1: The CARB fee goes up to $33.12

Every vehicle in Clean Truck Check pays a yearly compliance fee to CARB. The fee comes from Senate Bill 210, the 2019 law that created the program, and it’s adjusted every year to the California Consumer Price Index.

For 2027, CARB raised the fee from $32.13 to $33.12. The new amount applies to fees paid for compliance deadlines on or after January 1, 2027. CARB posts each year’s fee update by July 1 for the following year.

When it’s due: at your vehicle’s first compliance deadline of the year.
Where to pay: only in your CTC-VIS account, by credit card, debit card, or eCheck. CARB doesn’t accept paper checks or payments made through other CARB portals.
Browser tip: CARB recommends Microsoft Edge for CTC-VIS payments.
Timing: your compliance certificate shows up 1 to 2 business days after a card payment, or up to 7 business days after an eCheck. If DMV has a hold on your registration, allow another 3 to 5 business days for DMV to update.

This fee goes to the state, not to your tester. It’s separate from the cost of your emissions test, and CARB doesn’t refund fees paid by mistake, so only pay for trucks you own that run in California.

Change #2: Quarterly testing starts October 1, 2027

Since January 2025, most vehicles in Clean Truck Check have had two testing deadlines a year. Starting October 1, 2027, CARB requires passing tests four times a year, but only for vehicles with OBDII.

For Clean Truck Check, your vehicle has OBDII if it’s:

A diesel or diesel hybrid with a 2013 or newer engine
An alternative fuel or alternative fuel hybrid with a 2018 or newer engine

CARB goes by the engine’s model year, which isn’t always the same as the truck’s model year.

How deadlines are set today

California-registered trucks: your DMV registration expiration month, and again six months later. A truck that renews in March has deadlines in March and September.
Out-of-state trucks and DMV-exempt vehicles (like government trucks): based on the last digit of the VIN.

CARB says it will keep showing every deadline in CTC-VIS after quarterly testing starts. Look under the Testing Details tab on your My Entity page. Those are the dates CARB uses to decide whether you’re compliant, so go by CTC-VIS instead of guessing from the old schedule.

What this means for fleets: twice as many test dates for every newer truck, spread across the year by registration month or VIN. Getting a testing calendar set up before fall 2027 makes the switch a lot easier.

What’s not changing in 2027

There’s still no low-mileage exemption

Senate Bill 1064 would have limited testing to once a year for certain low-use trucks: California-registered, with 2012 or older engines, and driven fewer than 1,000 miles a year in the state. It passed the Legislature, but the Governor vetoed it on September 20, 2026. CARB’s FAQ confirms Clean Truck Check has no low-use exemption, so low-mileage trucks follow the same schedule as everyone else.

Out-of-state trucks

On January 27, 2026, the U.S. EPA announced a partial disapproval of California’s state plan as it relates to Clean Truck Check. In March 2026, CARB posted that the program’s requirements are still in effect for vehicles registered outside California while they operate in the state. If you run an out-of-state truck in California, CARB expects it to be reported, paid up, and tested.

The rules you already know

Test early: a passing test can be submitted up to 90 days before a deadline, which leaves time for repairs.
Credentialed testers only: tests have to be done by a CARB credentialed tester using CARB-certified equipment.
Notice to Submit to Testing: if CARB’s roadside monitoring flags your truck, you have 30 calendar days to submit a passing test.
Five-day pass: a truck that’s only in California briefly can get one five-day pass per calendar year. Request it by email at least 7 business days before entering the state.
DMV holds: for most DMV transactions, your truck has to be compliant, have no Clean Truck Check test or fee due within 90 days of its deadline, and have no open CARB enforcement action. If your deadline is close, take care of the test and fee before you go to DMV.
Brokers, ports, and railyards: freight contractors and brokers can only hire compliant trucks, and trucks that aren’t compliant can be turned away at ports and railyards.

Who has to do Clean Truck Check?

Nearly every diesel, alternative fuel, and hybrid vehicle with a gross vehicle weight rating over 14,000 lbs that drives on California roads, including:

Trucks, buses, motorcoaches, and shuttles
Government vehicles
Personal-use vehicles and one-truck owners
California-registered motorhomes
Vehicles registered outside California (except out-of-state motorhomes)

Not included: zero-emission vehicles, emergency vehicles, military tactical vehicles, vehicles with historical plates, vehicles under a CARB experimental permit, and motorhomes registered outside California. Gasoline vehicles aren’t part of Clean Truck Check.

Clean Truck Check vs. Smog Check

These are two separate programs. Clean Truck Check is run by the California Air Resources Board (CARB). Smog Check is run by the Bureau of Automotive Repair (BAR). They cover different vehicles and have different rules, and passing one doesn’t count for the other.

Your 2027 checklist

Log in to CTC-VIS. Make sure every truck is reported and active, and deactivate any you’ve sold.
Write down your dates. CTC-VIS also emails a monthly summary of anything due in the next 90 days.
Pay the $33.12 fee before your first 2027 deadline.
Test early. Testing up to 90 days ahead gives you room to fix a problem.
Fix warning lights first. Don’t test right after clearing codes or disconnecting the battery. Drive normally for a few days first.
Plan for fall 2027. Add the extra quarterly tests to your maintenance calendar now. Larger fleets can ask DMV about lining up registration dates.
Keep your certificate handy. Download and print it from CTC-VIS.

More prep tips: What to bring to your Clean Truck Check.

Free Clean Truck Check deadline tracker

Keeping track of two deadlines a year per truck, soon four, is a lot. Our free tracker does the math for you.

Type in each truck’s registration date and it shows both yearly deadlines
It shows when to book each test so there’s time for repairs
It turns red when a truck has less than 30 days left
It flags OBDII trucks that go to four tests a year in October 2027

Want us to keep track for you? Fill in the tracker and email it back. We’ll reach out when it’s time to test.

Email us for the free tracker, or text (626) 551-4555 and we’ll send it over.

Mobile Clean Truck Check testing in the San Gabriel Valley

Darling Smog is a woman- and veteran-owned emissions testing business on Route 66 in Glendora. We test trucks, RVs, and fleets at your yard, job site, or home, or at our shop, and we submit your results to CARB. We only test.

OBDII testing for 2013 and newer diesel and 2018 and newer alternative fuel engines
Smoke opacity testing and visual inspections for older diesel trucks
Motorhomes and RVs
Whole fleets lined up in one trip

We serve Glendora, Azusa, Covina, West Covina, La Verne, San Dimas, Citrus, Duarte, Baldwin Park, Irwindale, Monrovia, Arcadia, Pasadena and nearby.

Got a Notice to Submit or a deadline coming up? Text us the day you get it at (626) 551-4555.

Clean Truck Check 2027 FAQ

When does Clean Truck Check go to quarterly testing?

October 1, 2027, for vehicles with OBDII. Older trucks without OBDII stay at two tests a year.

How much is the Clean Truck Check fee in 2027?

$33.12 per vehicle, up from $32.13. It applies to compliance deadlines on or after January 1, 2027.

Does quarterly testing apply to my motorhome?

Not if it’s a California-registered motorhome for personal or emergency use. Those stay on once-a-year testing. Motorhomes used for business follow the regular schedule.

Is there a low-mileage exemption?

No. A bill that would have limited testing for some low-use trucks (SB 1064) was vetoed in September 2026.

Do out-of-state trucks still need Clean Truck Check?

CARB says yes, whenever they operate in California. CARB posted this in March 2026, after EPA’s partial disapproval in January 2026.

How early can I get tested?

Up to 90 days before your deadline.

What happens if I miss a deadline?

Your truck can get a DMV registration hold, and CARB can take enforcement action. CARB’s FAQ points to state law that allows civil penalties of $1,000 to $10,000 per day, per vehicle.

Where do I find my exact due dates?

In your CTC-VIS account at cleantruckcheck.arb.ca.gov, under the Testing Details tab on your My Entity page.

Sources

Everything on this page comes from these official pages. Rules can change, so CARB’s site and your CTC-VIS account always have the final word.

This page is general information, not legal advice.

Got trucks that need testing?

Pick a few days that work and we'll come to your yard. Local visits are free.

Pick my fleet days Text us

Or call 626-551-4555

CARB Clean Truck Check 2027 Changes: Quarterly Testing & the New Fee