Clean Truck Check:
What It Is & How to Get Certified

The Clean Truck Check Program, introduced by CARB, ensures that heavy-duty vehicles meet emissions standards to reduce pollution and improve air quality. If you operate or service diesel trucks in California, understanding the program and getting certified as a tester is essential for compliance and business growth. Here’s what you need to know and how to get started today.

Part 1: What is the Clean Truck Check Program?

The Clean Truck Check Program, introduced by the California Air Resources Board (CARB), is designed to reduce emissions from heavy-duty trucks and buses. It ensures that emissions control systems remain functional throughout a vehicle’s service life, helping California meet air quality standards and protect public health.

Who Needs to Comply?

All diesel, alternative fuel, and hybrid trucks & buses over 14,000 lbs. GVW

This includes any heavy-duty vehicle operating in California, regardless of fuel type or fleet size. If it exceeds 14,000 lbs GVWR, it must comply with Clean Truck Check testing requirements.

In-state and out-of-state vehicles that operate in California

Even if a vehicle is registered outside California, it must comply if it drives within the state. CARB enforces this through roadside monitors and DMV data matching.

Testing Requirements

01.
Biannual Emissions Testing (Quarterly Starting 2027)

Every eligible vehicle must complete emissions testing twice per year under current regulations. Starting in 2027, most vehicles will be required to test quarterly, increasing compliance frequency across the state. Staying ahead of this shift ensures uninterrupted operations and helps avoid penalties or registration delays.

02.
OBD-Equipped Vehicles

Vehicles with onboard diagnostics—typically 2013 and newer diesel engines or 2018 and newer alt-fuel engines—can be tested remotely using a CARB-certified device. These tests are fast, simple, and don’t require a shop visit, making them ideal for mobile service or fleet-side compliance. Digital reporting makes the process seamless for operators and testers alike.

03.
Older Vehicles

Trucks without onboard diagnostics—generally older than 2013—must undergo traditional smoke opacity testing and a visual inspection of emissions systems. These tests verify that the vehicle remains within legal emissions thresholds and has no tampering or faulty components. While more manual, they’re still essential to ensure compliance for legacy fleets.

04.
Automated Monitoring

CARB uses roadside emissions monitors to identify high-emitting vehicles in real time. If a vehicle is flagged, owners receive a Notice to Submit to Testing (NST) and must complete a certified test to confirm compliance. Vehicles that remain non-compliant may face registration holds and are prohibited from entering California ports and airport facilities.

Why This Matters To You

With over 1 million heavy-duty vehicles on California roads, emissions from trucks and buses account for over 50% of mobile pollution, making enforcement a priority. Non-compliance can lead to costly fines, registration holds, and enforcement actions, impacting business operations. By becoming a certified tester, you can help fleets stay compliant, avoid downtime, and unlock new business opportunities in a growing market.

Over 1 Million
Affected Vehicles

Trucks & buses make up 3% of California vehicles but contribute 50%+ of mobile emissions

Failure to Comply = Fines & Penalties

Non-compliance may lead to fines, registration holds, and enforcement actions

Fleet Efficiency & Business Growth

Certified testers can provide on-site testing solutions, helping fleets avoid downtime

Your Path to Certification & New Opportunities

Part 2: How to Get Certified as a Tester

Becoming a CARB-Certified Clean Truck Check Tester is simple, fast, and requires no ASE certification.

Become a Certified Tester in Just 3 Steps

Whether you’re a fleet operator managing your own compliance or a service provider looking to add a new revenue stream, certification is your first step to staying ahead of California’s Clean Truck Check requirements.

Step 1:

Watch the Training Videos

CARB provides six short videos that walk you through:

• Emissions testing procedures
• How to use the testing device
• How to submit test results to CARB

🕒 Total time: Under 2 hours

Step 2:

Take the Open-Book Exam

Once you’ve watched the training, take the 20-question open-book test. You can refer back to the videos as you go.

📖 It’s open-book for a reason—this process is designed to be accessible. If you don’t pass the first time, you can retake the test immediately with no penalty.

Step 3:

Get Certified Instantly

Pass the test, and you’re done.

You’ll receive your Clean Truck Check tester credential immediately—ready to start testing that same day.

Who Can Get Certified?

Anyone responsible for maintaining or operating heavy-duty vehicles in California can become a certified tester. Whether you manage a fleet, run a repair shop, work as a mobile diesel tech, or drive your own rig, the Clean Truck Check program makes it easy to take control of compliance. No special licenses or credentials are required—just a willingness to complete the quick training and start testing.

Fleet Managers
Mechanics & Service Shops
Mobile Diesel Techs
Owner-Operators
Anyone operating heavy-duty vehicles in California
Anyone can get certified—as long as they pass the test.

📘 Need More Information About the Test?

To become a credentialed tester for the Clean Truck Check program, you’ll need to complete CARB’s official training and open-book exam. The free online course includes six short modules covering all regulatory requirements and testing procedures. Once you pass with a score of 80% or higher, you’ll receive your official Tester ID and certificate.

👉 Click here to access the CARB Tester Training Course & Exam

📝 Important: Be sure to use a unique email address when registering, and double-check that it matches the one you’ll use with your testing device—this is critical to avoid tester ID errors.
If you’d like to be listed on CARB’s public directory of for-hire testers, don’t forget to check the box during registration.

For questions about the training or testing requirements, you can also contact CARB directly at [email protected] or call (866) 634-3735.

Get the Right Tools to Make It Happen

Choose a CARB-certified device that lets you test anywhere, anytime—no shop required.

Find My Device

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