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Starting January 2025, California requires semi-annual Clean Truck Check testing for diesel trucks. Miss it, and the DMV puts a registration hold on your vehicle. That means your truck sits, your business stops, and you’re scrambling to fix it.
You don’t have time for that. Your fleet needs to move, your drivers have routes, and your customers expect delivery. CARB compliant testing keeps your registration active and your trucks operational.
We bring the test to you. Our mobile service comes to your yard, your job site, or wherever your trucks are parked in South Pasadena, CA. You schedule it, we show up, and your vehicles get tested without burning half a day in traffic or waiting in line. The results go straight to CARB’s system, and you get documentation on the spot.
We’ve been CARB certified for over two years. We’ve completed more than 250 Clean Truck Checks across Los Angeles County, including South Pasadena, CA and the surrounding areas. We’re licensed, insured with $2 million in liability coverage, and we carry the mobile service rider that most testing companies skip.
South Pasadena, CA sits right in the middle of major freight corridors. Trucks moving between the ports, downtown LA, and the San Gabriel Valley pass through here daily. That means local fleets and owner-operators face the same compliance pressure as the big carriers. We work with construction companies, logistics operators, waste haulers, and anyone running heavy-duty diesel equipment in this area.
You’re not dealing with a national chain or a guy with a scanner in his trunk. You’re working with a local operation that knows California’s diesel regulations and shows up when we say we will.
First, you contact us and schedule a time. We ask for your vehicle details—year, make, model, VIN, and GVWR. If your truck is model year 2013 or newer and weighs over 14,000 pounds, it qualifies for OBD-based Clean Truck Check testing. Older trucks or lighter vehicles don’t fall under this program.
We arrive at your location in South Pasadena, CA with CARB-approved testing equipment. The test connects to your truck’s onboard diagnostics system and checks emissions performance through the OBD port. We’re looking at your SCR system, diesel particulate filter, and other emissions controls to confirm everything meets California standards.
The test takes about 20 minutes per vehicle. If your truck passes, we upload the results to CARB’s CTC-VIS system immediately. CARB and the DMV update your vehicle record, and you receive a certificate showing compliance. If something flags during the test, we give you a diagnostic report that shows exactly what needs attention before you retest.
You don’t need to prep the truck or do anything special. Just make sure the vehicle is accessible and the engine is in normal operating condition. We handle the rest.
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You get a CARB-credentialed tester who’s passed the state’s official training and exam. You get equipment that meets SAE J1667 specifications and CARB compliance standards. You get same-day service in most cases, and you get results uploaded to the state system before we leave your site.
South Pasadena’s proximity to major industrial zones means your trucks are likely running routes that put serious hours on emissions systems. The 710, 110, and 10 freeways all funnel through this area, and heavy stop-and-go traffic can stress diesel particulate filters and SCR components. Regular testing catches issues before they turn into expensive repairs or failed inspections.
California’s Clean Truck Check program covers roughly one million heavy-duty vehicles statewide. These trucks represent only 3% of vehicles on the road but produce over half of the state’s nitrogen oxide pollution. That’s why CARB enforcement is strict and why penalties for non-compliance start at $1,000 per violation and can climb to $75,000 per day depending on severity.
Mobile testing saves you fuel, time, and the hassle of pulling trucks off jobs. You keep your fleet moving, and you stay ahead of the twice-a-year testing requirement without disrupting operations.
Any diesel truck with a gross vehicle weight rating over 14,000 pounds and a model year of 2013 or newer falls under the Clean Truck Check program. This includes semi-trucks, box trucks, dump trucks, concrete mixers, and diesel motorhomes that meet the weight threshold.
The 2013 cutoff matters because that’s when California required OBD systems on heavy-duty diesel engines. The test uses your truck’s onboard diagnostics to check emissions performance. Older trucks without OBD systems aren’t part of this program, and lighter vehicles under 14,000 pounds don’t qualify either.
If you’re not sure whether your truck qualifies, check the VIN plate or registration. GVWR is listed there. If it says 14,001 pounds or higher and the model year is 2013 or later, you need testing twice a year starting in 2025.
If your truck fails, you get a diagnostic report showing which emissions system triggered the failure. Common issues include malfunctioning SCR systems, clogged diesel particulate filters, or faulty sensors that prevent the OBD system from reading correctly.
You have 30 days from the failure notice to fix the problem and retest. During that time, your truck can still operate, but you need to submit a passing test before the deadline. If you don’t, CARB can place a registration hold with the DMV, which prevents you from renewing your registration.
Most failures are fixable. Sometimes it’s a sensor, sometimes it’s a software update, sometimes it’s a component that needs replacement. The diagnostic report tells you exactly what’s wrong, so you’re not guessing. Once repairs are done, you schedule a retest, and if the truck passes, the results go to CARB and the hold gets lifted.
No. Regular smog check stations that test passenger cars don’t have the equipment or certification for Clean Truck Check testing. This is a separate program that requires CARB-credentialed testers and specialized OBD testing devices approved for heavy-duty diesel engines.
You need to work with a provider who’s completed CARB’s training course, passed the credentialing exam, and uses approved testing equipment. Not every mobile mechanic or diesel shop qualifies. CARB maintains a list of credentialed testers, and results must be uploaded through the CTC-VIS system to count as official.
Mobile testing is legal and often more convenient than driving to a fixed location. There’s no requirement to visit a brick-and-mortar station for heavy-duty trucks. As long as the tester is credentialed and the equipment is CARB-approved, the test is valid no matter where it happens.
You need to test twice a year. CARB sets specific testing windows based on your vehicle’s registration month. You’ll receive notices telling you when your truck is due, and you have a set period to complete and submit a passing test.
The semi-annual requirement started January 1, 2025. Before that, the program was voluntary or limited to certain fleets. Now it’s mandatory for all qualifying vehicles. If you operate multiple trucks, each one has its own testing schedule based on its individual registration.
Missing a test deadline triggers a 30-day notice. If you still don’t comply after that, the DMV registration hold kicks in. That means you can’t renew your registration, and technically, you’re not supposed to operate the vehicle on public roads. For a business that depends on trucks, that’s a serious problem. Staying on schedule keeps you compliant and avoids the scramble to fix things after a hold is already in place.
A smog check tests light-duty vehicles like cars, SUVs, and small trucks under 14,000 pounds. It measures tailpipe emissions and checks for tampering with emissions equipment. Most people are familiar with smog checks because they’re required every two years for passenger vehicles in California.
Clean Truck Check is a separate program for heavy-duty diesel trucks over 14,000 pounds. Instead of measuring tailpipe emissions, it uses the truck’s OBD system to check whether emissions controls are working properly. The test looks at your SCR system, diesel particulate filter, and other components that reduce nitrogen oxides and particulate matter.
The equipment is different, the certification is different, and the reporting system is different. You can’t use a regular smog check to satisfy Clean Truck Check requirements, and you can’t take a heavy-duty diesel to a standard smog station and expect them to handle it. The programs don’t overlap.
Not much. Your truck should be in normal operating condition with no warning lights on the dash. If your check engine light is on or your OBD system is throwing codes, the test will likely fail. Get those issues checked before scheduling.
Make sure the truck is accessible. If it’s buried behind other equipment or parked in a tight spot, we’ll need room to get to the OBD port and set up the testing equipment. The engine doesn’t need to be warm, but it should start and idle normally.
You don’t need to clean the truck or do any special prep. We’re testing the emissions system through the OBD port, not doing a visual inspection or measuring tailpipe output. As long as the truck runs and the OBD system is functional, we can complete the test. If something’s wrong, we’ll catch it during testing and give you a report so you know what to fix.
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