How to Apply for CARB Certification: Review and Executive Order

To apply for CARB certification, you identify the correct product category under California Code of Regulations Title 13, build a technical package covering your engine family, emission test data, durability demonstration, labeling, on-board diagnostics, and warranty, then submit through CARB’s Document Management System with the required fee and work with an assigned certification engineer through review to an Executive Order. One thing to know before you start: CARB certification runs concurrently with U.S. EPA certification, and a product holding only EPA approval is still illegal to sell in California.¹ Selling an uncertified new vehicle, engine, or regulated piece of equipment can bring civil penalties of up to $37,500 per violation.²

Figure Out Which Category Applies

The first real step is determining which regulatory category your product falls into. Title 13 divides products into groupings with their own emission standards and test protocols: on-road light-duty vehicles, on-road heavy-duty engines, off-road compression-ignition engines, off-road large spark-ignition engines, off-highway recreational vehicles, and small off-road engines.³ Category is driven by intended use, engine displacement or power output, and vehicle weight class. Get this wrong and you’ll be running the wrong test cycle against the wrong emission limits, which means a rejected application.

When a product could arguably fit in two categories, the more stringent standard generally applies. Confirm your category before you spend money on testing.

Assemble the Technical Package

Incomplete packages are the single most common reason applications stall. CARB’s review staff will evaluate engine family specifications, emission control systems, test data, durability demonstrations, labeling, and warranty coverage, and each of those needs to be in the file when you file.

Engine Family and Emission Testing

Define your engine family first: the group of engines sharing similar cylinder displacement, fuel systems, and power ratings. Every engine within the family must meet the same emission standards, so where you draw the family boundaries has real consequences. Emission testing is done at a laboratory meeting CARB’s standards, measuring nitrogen oxides, hydrocarbons, particulate matter, and other pollutants across operating conditions relevant to the product’s duty cycle.

Durability Data

CARB wants to know your emission controls will still work years from now. You have to submit durability data showing the emission control system holds up over the product’s entire useful life.⁴ That typically means running engines for hundreds or thousands of hours to simulate aging, then documenting deterioration factors that project how emissions will grow over time. Coverage short of the full useful life gets the application sent back.

Emission Control Labels

Every certified product carries emission control labels meeting the requirements of California Code of Regulations Section 1965.⁵ Your application specifies label content, its physical placement on the product, and the materials used for durability and tamper resistance. Label deficiencies are a common cause of delays on otherwise strong applications.

On-Board Diagnostics

For on-road vehicles, on-board diagnostics approval runs in parallel with certification review. You can submit your certification application before OBD approval is finalized, but CARB will not grant final certification until OBD is verified.⁶ Plan for that in your timeline. OBD documentation covers every diagnostic monitor, the thresholds triggering malfunction indicators, and how calibration changes affect those monitors.

Warranty and Maintenance

Your application must include warranty statements and maintenance instructions for the emission control system, including a list of all emission-related components and a clear service schedule.⁷ Warranty periods vary by category. For heavy-duty diesel vehicles over 14,000 pounds, the defects warranty runs five years or between 110,000 and 350,000 miles depending on the engine’s weight-class certification, whichever comes first.⁸ The warranty information you submit has to match the physical product.

Submit Through the Document Management System

Once your package is assembled, you file through CARB’s Document Management System (DMS), the electronic portal that handles submissions and tracks status. DMS also gives you direct communication with your assigned certification engineer, which matters once questions start coming back. Some aftermarket part categories can still be submitted by physical mail to CARB headquarters in Sacramento, but electronic filing is the norm and moves faster.

Fees are paid before CARB begins detailed evaluation, and they vary widely by category. Off-road engine families for the 2025 and subsequent model years carry base certification fees running from about $1,099 for an evaporative family to $4,511 for a large spark-ignition engine family, with reduced rates for carry-over certifications and low-volume manufacturers.⁹ On-road fees are higher. A specially constructed or specially produced vehicle engine package carries a base fee of $23,254 for the 2026 model year, with carry-over packages at $5,813. Fees for light-duty test groups, heavy-duty engine families, and other on-road categories are calculated from a formula in the regulations rather than a flat schedule.

What the Review Looks Like

The review runs in three stages.

Preliminary review takes up to 30 days from submission. CARB tells you whether the application is complete enough to proceed. The expectation is complete-at-submission, though staff may allow missing items to be provided during review.
Full staff review begins once the application is marked “Accepted for Filing.” An assigned certification engineer works through engine family names, weight classes, emission control systems, test data, durability data, certification levels, labeling, and warranty. CARB will provide substantive feedback or notice of completed review within 30 days of starting full review or since the last meaningful update.
Peer and management review closes the process. A second engineer and management verify the work. No updates or additions to the application are allowed at this stage unless CARB specifically requests them.

Total time from submission to approval depends on how complete your initial package is and how quickly you answer engineering questions.⁶ A carry-over certification can move through in a few weeks; a first-time certification for complex technology takes longer. Delays come from incomplete files and slow responses, not from CARB throughput.

The Executive Order

A successful application produces an Executive Order signed by the CARB Executive Officer. That document is your legal authorization to sell the certified product in California. It lists the specific models or engine families covered, any conditions of use, and the emission standards the product was certified to meet. Violating its terms can lead to revocation and civil penalties of up to $37,500 per violation.² For violations involving small off-road engines or portable fuel containers, the cap is $500 per unit.

After You’re Certified

Certification is not the finish line. It carries ongoing obligations.

In-Use Testing

Heavy-duty engine manufacturers are subject to the Manufacturer-run Heavy-Duty In-Use Testing Program. Each year CARB and the EPA select manufacturers and engine families for real-world emission testing on vehicles above 8,500 pounds gross vehicle weight rating. When you receive a test order, you must conduct on-road testing under normal operating conditions and submit results to both agencies within 18 months.¹⁰ Failing an in-use test can trigger enforcement or mandatory corrective action.

Voluntary Recalls

If you discover an emission-related defect after certification, a voluntary recall involving 25 or more engines requires a recall plan submitted to CARB at least 15 working days before owner notifications go out. The plan describes the defect, the number of engines affected, the proposed correction, and the notification method. A progress report is due no later than 18 months after notification begins, and you keep all recall records for at least five years from the manufacture date of the affected engines.¹¹

Selling Beyond California

Under Section 177 of the federal Clean Air Act, other states may adopt California’s motor vehicle emission standards, and a number have done so.¹² Adopted standards must be identical to the California standards for which a waiver has been granted, and adopting states don’t need separate EPA approval. For manufacturers, that means your CARB Executive Order is the baseline credential for selling in Section 177 states as well. You generally don’t file a separate certification application in each one, but individual state registration or notification requirements can vary and should be checked before you ship.

If Your Application Is Denied

You have the right to challenge a denial, suspension, or revocation. The appeal must be filed no later than 20 days from the date of the denial notice. You can choose a full administrative hearing or a review conducted entirely on written submissions.¹³

A written appeal must include a copy of the denial notification, the name and contact information of the person representing the manufacturer, a signed statement that the representative has full authority to act on the company’s behalf, and a detailed factual explanation of why the denial was improper. Vague or conclusory allegations are not accepted. Miss the 20-day window and the appeal can be dismissed, so calendar the deadline the day you receive an adverse decision.

1
California Air Resources Board. New Vehicle and Engine Certification – About
2
California Legislative Information. California Health and Safety Code 43016
3
Cornell Law School / Legal Information Institute. California Code of Regulations Title 13 1961.2 – Exhaust Emission Standards and Test Procedures
4
California Air Resources Board. On-Road Heavy-Duty and Off-Road Compression Ignition Certification Programs – Useful Life Compliance and Durability Demonstration
5
Cornell Law School. California Code of Regulations Title 13 1965 – Emission Control, Smog Index, and Environmental Performance Labels
6
California Air Resources Board. On-Road Heavy-Duty and Off-Road Compression Ignition Certification Programs – Certification Steps Overview
7
Legal Information Institute. California Code of Regulations Title 13 2787 – Warranty Requirements
8
Legal Information Institute. California Code of Regulations Title 13 2036 – Defects Warranty Requirements for 2004 and Subsequent Model Year Vehicles
9
Cornell Law School. California Code of Regulations Title 13 2906 – Certification Fees for Off-Road Mobile Sources
10
California Air Resources Board. Manufacturer-run Heavy-Duty In-Use Testing Program
11
Legal Information Institute. California Code of Regulations Title 13 2405.2 – Voluntary Emission Recall Program
12
US EPA. Vehicle Emissions California Waivers and Authorizations
13
Legal Information Institute. California Code of Regulations Title 17 94213 – Appeals