Clean Truck Check vs smog check vs PSIP

Short answer: Clean Truck Check is not the same as a regular smog check. Clean Truck Check is CARB's emissions testing program for most diesel and alternative-fuel vehicles over 14,000 lb GVWR that operate in California. Lighter vehicles generally fall under California's regular Smog Check program instead, which is a separate program with its own rules.

Clean Truck Check vs smog check: the core difference

People search for a "truck smog check" all the time, and it is easy to see why. Both are emissions tests. But they are different programs.

• Clean Truck Check is run by CARB (the California Air Resources Board). It covers most diesel and alternative-fuel vehicles over 14,000 lb GVWR operating in California, including out-of-state and international trucks. Owners report vehicles in CTC-VIS, pay CARB's annual compliance fee and pass tests on a schedule.
• California's regular Smog Check is a separate program, run through the Bureau of Automotive Repair (BAR), for passenger cars and other lighter vehicles. Check the DMV or BAR for what applies to a vehicle at or under 14,000 lb.

So the difference between CARB and BAR testing comes down to which program covers your vehicle. Weight, fuel type and how the vehicle is used all matter. For edge cases, check CARB's rules for your vehicle.

Diesel trucks: 14,000 lb or less vs over

The 14,000 lb GVWR line is the key number.

• Over 14,000 lb GVWR, diesel and alternative-fuel: most are covered by Clean Truck Check. That includes semis, box trucks, dump trucks, buses, refuse trucks, construction and agricultural vehicles and motorhomes over 14,000 lb, where they fall under the program.
• 14,000 lb or less: generally not Clean Truck Check. Check the regular Smog Check rules for your vehicle.

If you drive a heavy pickup or a work truck near the line, look at the GVWR on the door label and check CARB's rules before you book anything.

Can a STAR smog station test a truck over 14,000 lb?

A Clean Truck Check test has to be done by a credentialed Clean Truck Check tester using the right equipment, such as a CARB-verified OBD test for 2013 and newer diesel engines. Being a smog station, STAR or otherwise, is a different credential for a different program. If you are thinking about a local smog shop, ask whether it performs Clean Truck Check tests.

Which Clean Truck Check test does your truck need?

Clean Truck Check itself has different tests depending on the engine:

• 2013 and newer diesel: CARB-verified OBD test
• 2018 and newer alternative fuel: CARB-verified OBD test
• 2012 and older diesel without OBD: smoke opacity test plus visual inspection
• 2017 and older alternative fuel without OBD: visual inspection

Learn more about the OBD test and the smoke opacity test.

Clean Truck Check vs PSIP

PSIP, the Periodic Smoke Inspection Program, was CARB's older periodic smoke testing requirement for diesel fleets. Clean Truck Check is CARB's current heavy-duty inspection and maintenance program, and it is the one that drives today's CTC-VIS reporting, fees and test deadlines. If you have questions about how older PSIP records or requirements apply to your fleet, check CARB.

The practical takeaway: plan your testing around Clean Truck Check and the deadlines in CTC-VIS. Most covered vehicles currently test twice a year, with changes possible. See how often trucks need testing.

Clean Truck Check vs DOT and BIT inspections

Clean Truck Check is an emissions program. DOT inspections and California's BIT inspections are safety programs. They check different things, and passing one does not satisfy the other. If your trucks need both, plan for both.

Mobile testing vs a test station

A Clean Truck Check test is the same test whether a tester comes to you or you drive to a shop. What changes is the hassle.

• At a test station, a driver takes the truck off the road, drives to the shop, waits and drives back.
• With mobile testing, the tester comes to your yard, jobsite, terminal, port or home. The truck stays where it is, and one visit can cover a whole fleet.

For many owners, the lost time and fuel of driving to a shop costs more than the test. See can Clean Truck Check be done at my yard.

Common mix-ups to avoid

• "I passed a smog check, so I'm covered." A regular smog check does not count for Clean Truck Check, and the reverse is also true.
• "My truck is registered out of state, so this doesn't apply." Out-of-state and international trucks that operate in California are covered.
• "I paid the fee, so I'm done." The compliance fee and the tests are separate. A truck needs both, plus a report in CTC-VIS.
• "I'll deal with it at renewal." Non-compliance can lead to a DMV registration hold for California-registered trucks, plus CARB citations and penalties.

Quick guide: which test do I need?

1. Check the GVWR on the door label.
2. Over 14,000 lb, diesel or alternative fuel, operating in California? You most likely need Clean Truck Check. Report the truck in CTC-VIS; our CTC-VIS registration guide shows how.
3. At or under 14,000 lb? Check the regular Smog Check rules with the DMV or BAR.
4. Not sure? Check CARB's rules for your vehicle, or call us and we will help you read them.

How Diesel Dynamix helps

We are an independent Clean Truck Check testing service, not CARB or a government agency. We test on site anywhere in our Southern California area, from Los Angeles and the ports to the Inland Empire and San Diego. We help with CTC-VIS questions, explain results in plain English and give you the next due date for every truck.

• What Clean Truck Check requires
• Clean Truck Check FAQ
• Our services

Book a test, or call, text or WhatsApp (858) 342-8328.