Hear from Our Customers
You’re running a business, not studying CARB regulations full-time. But if your 2013 or newer diesel truck isn’t compliant, CARB will contact the DMV and block your registration. Your truck sits. Your revenue stops. Your customers wait.
That’s the reality for heavy-duty vehicle operators in California right now. Semi-annual CARB emissions testing became mandatory January 1, 2025 for trucks with 2013+ diesel engines over 14,000 pounds GVWR. If you get a Notice to Submit to Testing from CARB’s roadside monitoring, you have 30 days to provide passing results. Miss that window and you’re looking at registration holds, fines up to $10,000 per vehicle per day, and trucks pulled off the road until you’re compliant.
We handle the OBD testing, diagnostics, and certification so your fleet stays legal. You get documentation that satisfies CARB, keeps the DMV happy, and protects your ability to operate in California. No drama. No downtime you didn’t plan for.
All SMOG Motors is a CARB certified testing facility in Los Angeles specializing in heavy-duty diesel trucks. We’re not a general smog shop trying to figure out your OBD system on the fly. We work with 2013 and newer model year trucks every day—the exact vehicles facing these new compliance requirements.
Los Angeles has roughly a million heavy-duty trucks and buses operating under CARB regulations. You’re not alone in trying to navigate this. We’ve helped fleet operators, owner-operators, and out-of-state truckers get compliant fast so they can get back to work. Our facility is set up specifically for the diagnostics and testing your truck needs, and we understand the urgency when you’re on a deadline.
You bring your 2013 or newer diesel truck to our Los Angeles facility. We run the OBD emissions test that CARB requires—this checks that your emissions control equipment is working properly. The test pulls data directly from your truck’s onboard diagnostics system.
If everything passes, we provide your certificate right away. You get the documentation you need for CARB and DMV. If there’s an issue, we identify what needs repair so you can get it fixed and come back for a retest. No guessing. No vague explanations.
The whole process is designed to be straightforward. You’re not sitting around for hours. We know your truck being off the road costs you money, so we move efficiently. Most tests are completed same-day, and you leave with proof of compliance or a clear plan to get there.
Ready to get started?
This is OBD emissions testing for trucks with 2013 or newer diesel engines and a GVWR over 14,000 pounds. That’s it. If your truck is older than 2013 or weighs less than 14,000 pounds GVWR, this service doesn’t apply to you.
For qualifying trucks, you get a full diagnostic scan of your emissions control systems, a CARB-compliant test, and official certification if you pass. We check for fault codes, verify your diesel particulate filter and selective catalytic reduction systems are functioning, and confirm your truck meets California’s emissions standards. This is what CARB and the DMV need to see.
In Los Angeles, where heavy-duty trucks make up only 3% of vehicles but produce over 50% of nitrogen oxides and diesel particulate pollution, enforcement is serious. CARB has been using roadside monitoring devices since January 2023. If your truck triggers a violation, you’ll get that Notice to Submit to Testing. We’re here to help you respond to that notice—or better yet, stay ahead of it. Starting October 2027, testing frequency increases to quarterly for OBD-equipped vehicles, so getting this dialed in now saves you headaches later.
If your truck doesn’t pass, we give you a detailed report showing exactly what triggered the failure. Usually it’s a fault code related to your diesel particulate filter, DEF system, or another emissions component. You’ll need to get those repairs done at a qualified diesel mechanic.
Once the repairs are complete, bring your truck back and we’ll retest it. You only pay for the retest, not a full new inspection. We don’t do the repairs ourselves—we just handle the testing and certification. This keeps things transparent and lets you choose who works on your truck.
The key is not to ignore a failure. CARB doesn’t care why your truck failed. They care that you fix it and prove compliance within their deadline. If you received a Notice to Submit to Testing, that 30-day clock is ticking whether your truck is in the shop or not.
Right now, most trucks with 2013+ diesel engines need testing twice a year—that’s the semi-annual requirement that started January 1, 2025. The exact frequency can depend on your truck’s specific configuration and CARB’s classification, but semi-annual is standard for the majority of heavy-duty diesel trucks over 14,000 pounds GVWR.
Starting in October 2027, the requirement changes to quarterly testing for OBD-equipped vehicles. That means every three months instead of every six. CARB is tightening the schedule because they want continuous verification that emissions systems are working, not just periodic snapshots.
If you get a Notice to Submit to Testing from CARB’s roadside monitoring program, you have to test within 30 days regardless of when your last test was. Those notices go out when CARB’s remote sensors detect a potential violation. It’s not optional—you either comply or face registration holds and penalties.
It has to be a CARB certified testing facility. CARB only accepts results from facilities they’ve officially authorized to perform heavy-duty vehicle emissions testing. Random smog shops that handle passenger cars can’t do this. The equipment, training, and certification requirements are different.
When you’re choosing where to go, make sure the facility specifically handles 2013+ diesel trucks and OBD testing. Not every CARB certified location has experience with heavy-duty vehicles. You want a place that knows the systems in your truck and can run the test correctly the first time.
We’re set up for exactly this type of testing in Los Angeles. You’re not our side project—heavy-duty diesel compliance is what we do. That means we have the right diagnostic tools, we understand the CARB requirements, and we can answer your questions without having to look things up.
Bring your vehicle registration and a valid ID. If you received a Notice to Submit to Testing from CARB, bring that too—it has information we’ll need to report your results back to CARB properly. If you’re an out-of-state operator, bring whatever documentation shows your truck operates in or through California.
You don’t need past test results or repair records unless you’re coming back for a retest after repairs. In that case, it’s helpful to have documentation of what was fixed, but it’s not required. We’re mainly concerned with what your truck’s OBD system shows us right now.
Make sure your truck is in operational condition when you bring it in. We can’t test a truck that won’t start or has major mechanical issues preventing normal operation. If your check engine light is on, that’s likely going to trigger a failure, so you might want to get that diagnosed first. We can still test it, but you’ll probably be coming back for a retest after repairs.
Testing costs vary depending on your truck’s configuration and what’s required, but you’re typically looking at a few hundred dollars for the OBD emissions test and certification. That’s significantly less than the penalties for non-compliance. CARB fines start at $300 per vehicle and can reach $10,000 per vehicle per day for serious violations.
If your truck fails and needs a retest after repairs, there’s a retest fee, but it’s lower than the initial test cost. Some facilities charge extra for rush service or after-hours testing. We keep our pricing straightforward—you know what you’re paying before we start.
The real cost isn’t the test itself. It’s what happens if you don’t test. Registration holds mean your truck can’t legally operate. That’s lost revenue every day it sits. Add potential fines, the cost of getting your registration reinstated, and the administrative headache of dealing with CARB and DMV, and suddenly a few hundred dollars for testing looks like the smart investment it is.
If your truck operates in California—even if it’s just passing through—you need to comply with CARB regulations. It doesn’t matter where your truck is registered. California law applies to any heavy-duty vehicle operating on California roads. CARB’s roadside monitoring devices don’t care about your license plate. They’re scanning emissions from every truck that passes.
Out-of-state operators get caught by this all the time. You’re hauling through California, CARB’s sensors flag your truck, and suddenly you’re getting a Notice to Submit to Testing. You have 30 days to provide proof of compliance or face penalties. If you ignore it, CARB can pursue enforcement even across state lines, and you’ll have problems the next time you enter California.
The cleanest approach is to get tested proactively if you regularly run California routes. It’s cheaper and easier than dealing with a violation notice when you’re on a tight delivery schedule. We work with out-of-state truckers regularly. Bring your truck in, get the test done, and you have documentation proving compliance for the next six months.
Local Resources
Useful Links
Other Services we provide in Los Angeles
