California Air Resources Board

Manufacturers of add-on and modified parts planning to sell, offer for sale, or advertise their product for use in California vehicles should apply for an exemption from Vehicle Code Section (VC) 27156. A VC 27156 exemption is granted if the product has been determined not to cause any increase in vehicular emissions. The first step to obtain an exemption is to submit an application to the California Air Resources Board (CARB). Detailed information on how to apply is available in the Procedures for Exemption of Add-On and Modified Parts document, adopted June 29, 2021. For these Procedures effective January 1, 2022, there are twelve types of forms available; manufacturers must fill out the form appropriate for their product. Each form is available by clicking the associated link, below. 

Category I

• Consolidation of Existing Executive Orders

• Model-Year Additions on Carryover Vehicle(s) or Engine(s)

• Part Number(s) or Name Change(s)

• Private Label(s) or Extending Coverage to Subsidiaries

Category II

• Air Intake Kits or Modifications

Category III

• Engine Control Module (ECM) Programmers and/or ECM Signal Modifications

Category IV

• Fuel Tanks or Fuel Tank Modifications

Category V

• Intercooler Kits Intercooler Components or Modifications

Category VI

• Supercharger and Turbocharger Kits or Modifications

Category VII

• Pre-Catalyst Exhaust Components

Category VIII

• Other Categorized Parts

Category IX

• Add-On or Modified Part(s) Not Covered by Categories II through VIII

The forms below were used for applications submitted prior to January 2022 and for other Aftermarket Parts Programs that require the use of these forms.

Form A

General Criteria Parts Application: this must be filled out for those add-on and modified parts for which vehicle or engine emission testing may be required to determine their impact on emissions.

Form B

Compliance Criteria Parts Application: this must be filled out for those parts for which explicit criteria are satisfied in writing, and which do not require vehicle or engine emission testing to obtain the VC 27156 exemption. Parts eligible for compliance criteria evaluation are exhaust headers for non-feedback controlled catalyst-equipped vehicles, intake manifolds for non-EGR vehicles only, ignition system components (excluding distributors), ignition distributors, and intercoolers.

Form C

Application for Turbochargers/Superchargers: this must be filed for systems which include a turbocharger or supercharger.

Once the application has been filed, the CARB will contact you to inform you of missing information or to specify test vehicles. You are responsible for obtaining the vehicles and having them tested at a qualified independent laboratory. If you have any questions concerning the suitability of a vehicle for testing or the test themselves, please contact the staff engineer assigned to your application. If confirmatory testing is required at CARB's laboratory after you completed the testing, you must provide the test vehicle, but there is no charge for testing.

Manufacturers must present sufficient information to establish that an emissions increase will not result from the use of an add-on or modified part. If your device or modification is exempted, CARB will issue an Executive Order stating that the part will not adversely affect emissions and that it is legal for sale and use in California.

Please submit the completed application along with the necessary documents electronically using CARB’s eFILE system.

Learn how to get an eFILE account at the following link:

Procedures to Obtain / Modify an eFILE Account | California Air Resources Board