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Your truck clears the test. Your registration doesn’t get flagged. You don’t get pulled off the road during a CHP inspection.
That’s what compliance looks like. No DMV hold blocking your registration renewal. No $10,000-per-day fines piling up because you missed a deadline. No scrambling to find a credentialed tester the week your truck’s due.
Starting January 1, 2025, every heavy-duty diesel truck model year 2013 or newer with a GVWR over 14,000 pounds needs a passing Clean Truck Check to stay registered in California. If you operate in this state, this isn’t optional. It’s the law, and CARB is enforcing it.
The test itself takes 15 to 30 minutes. It’s an OBD scan of your truck’s emissions system. If it passes, we submit the results to CARB, and you’re clear for your compliance period. If it doesn’t, you have up to 90 days before your deadline to get repairs done and retest.
You can’t register. You can’t legally operate. And if you’re caught running non-compliant, the penalties add up fast.
All SMOG Motors is a CARB-credentialed testing facility in Paramount, CA. That means we’ve completed the state-required training, passed the exam, and we’re authorized to perform Clean Truck Check testing on heavy-duty vehicles.
Paramount sits right in the middle of one of the busiest logistics corridors in the country. We’re surrounded by trucking companies, owner-operators, and fleets running the I-710 and I-5 daily. We know what’s at stake when a truck gets sidelined.
We don’t work on older trucks or lighter vehicles. This service is specifically for 2013 and newer diesel trucks over 14,000 pounds GVWR. If your truck qualifies, we’ll test it right and get your results submitted the same day.
You schedule an appointment or stop by during business hours. Bring your truck, your registration, and about 20 minutes.
We connect a CARB-certified OBD device to your truck’s diagnostic port. The scan pulls data from your engine’s emissions system—things like sensor readiness, fault codes, and system performance. We’re not guessing. We’re reading what your truck is already tracking.
If everything checks out, you pass. We submit your results directly to CARB, and they update your compliance status. You’ll get documentation showing you’re clear until your next deadline.
If the system flags an issue, we’ll tell you what it is. You’ll have time to get it repaired before your compliance deadline hits. You can retest up to 90 days in advance, so there’s room to handle repairs without losing your registration.
The whole process averages under 20 minutes for most trucks. No disassembly. No downtime beyond the test itself. You’re in, you’re scanned, you’re done.
Ready to get started?
This regulation applies to nearly all heavy-duty diesel and alternative fuel trucks operating in California. If your truck is a 2013 or newer diesel engine, or a 2018 or newer alternative fuel engine, and it’s over 14,000 pounds GVWR, you’re required to test.
Right now, testing is required twice a year. Starting October 2027, OBD-equipped vehicles will need to test four times a year. The compliance fee for 2025 is $31.18 per test, and that goes to CARB, not the testing facility.
Paramount is a hub for interstate trucking. If you’re an out-of-state operator running loads through California, you’re still subject to this regulation. CARB and CHP have enforcement authority, and they’ve been using roadside emissions monitoring since January 2023. If your truck gets flagged, you’ll be required to test.
The consequences for skipping compliance aren’t small. DMV registration holds mean your truck can’t be renewed or registered. Fines can reach $10,000 per vehicle per day. And if you’re running a fleet, that adds up across every non-compliant truck.
Testing ahead of your deadline is allowed. You can submit a passing test up to 90 days early. That gives you a buffer if repairs are needed or if your schedule is tight.
The test itself typically runs between $60 and $140, depending on the facility and whether it’s done on-site or at a shop. That’s separate from the $31.18 compliance fee that CARB charges for 2025, which is paid when your results are submitted.
Mobile testing services cost more because they come to you. If you’ve got a fleet or your trucks are already staged somewhere, that convenience might be worth it. If you’re running a single truck, coming to our shop in Paramount is usually the faster and cheaper option.
If your truck doesn’t pass the first time, you’ll need to pay for repairs and then pay for a retest. That’s why testing early matters. You don’t want to be up against your compliance deadline with a truck that needs work.
If your truck fails, you’ll get a report showing what triggered the failure. It could be a sensor issue, a fault code that hasn’t been cleared, or an emissions system component that’s not performing to spec.
You’ll need to get the issue repaired by a qualified mechanic. Once the repair is done, you come back for a retest. You’re allowed to retest as many times as needed before your compliance deadline, but each test costs money and takes time.
The 90-day advance testing window exists for this exact reason. If you test early and fail, you’ve got time to fix the problem without losing your registration or getting hit with penalties. If you wait until the last minute and fail, your truck is off the road until it passes.
Yes. If your truck is registered in California and meets the weight and model year requirements, it needs to comply regardless of how often you drive it. The regulation doesn’t make exceptions for low-mileage vehicles or trucks that sit idle most of the year.
Even if you’re only using your truck for personal use—like a diesel motorhome over 14,000 pounds GVWR—you still fall under the rule if it’s a 2013 or newer model. CARB’s regulation is based on vehicle type and weight, not usage frequency.
If your truck isn’t compliant, the DMV will place a registration hold. That means you can’t renew, and you can’t legally operate it on California roads. It doesn’t matter if you only drive it twice a year.
You can submit a passing test up to 90 days before your compliance deadline. That’s a three-month window to get ahead of the requirement and avoid any last-minute issues.
Testing early is smart if you’re not sure about your truck’s emissions system or if you’ve had check engine lights recently. If something’s wrong, you’ll have time to get it fixed and retest before your deadline hits.
If you wait until the week before your deadline and your truck fails, you’re stuck. Repairs take time. Parts might need to be ordered. You could miss your deadline, lose your registration, and rack up penalties while your truck sits.
No. The test has to be performed by a CARB-credentialed tester. Not every smog shop is certified to do Clean Truck Check testing. CARB maintains a list of credentialed testers, and you need to go to one of them.
All SMOG Motors is a credentialed facility in Paramount. We’ve completed the required training and we use CARB-certified OBD testing equipment. If you go to a shop that’s not credentialed, the test won’t count and you’ll have to do it again somewhere else.
If you’re based in the Paramount area or you’re running through the LA logistics corridor, we’re set up to handle your testing quickly. You don’t need to drive across the county to find a credentialed shop.
Trucks older than model year 2013 are currently exempt, as are trucks under 14,000 pounds GVWR. If your truck runs on gasoline instead of diesel or alternative fuel, it’s also not subject to this regulation right now.
But if your truck is a 2013 or newer diesel, or a 2018 or newer alternative fuel vehicle, and it’s over 14,000 pounds, it’s covered. That includes semi trucks, box trucks, dump trucks, buses, and even large motorhomes that meet the weight threshold.
There are some exemptions for certain government and military vehicles, but those are narrow. If you’re operating commercially or privately in California and your truck fits the criteria, assume you need to comply unless you’ve confirmed otherwise with CARB.
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