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Cars and Light Trucks

Vehicle Programs and Compliance Guidance Letters

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Search the Document Index System (DIS) database to find:

  • Advisory Circulars
  • Applications for Certification
  • Certificates of Conformity
  • Certificate Summary Information Reports
  • Manufacturer Guidance Letters
  • Verify System Documentation

Change in Process for Guidance Letter Distribution

A list server has been established to notify industry of new guidance letters posted to this website. EPA will no longer distribute letters by email. For more information on the notification process and to sign up for the list server see Guidance Letter: Change in Process for Guidance Letter Distribution (CISD-08-03) (PDF) (2 pp, 56K, About PDF)

EPA Guidance letters are used by EPA to provide information, guidance and instructions to the regulated automotive industry on specific compliance topics and issues. The regulated industry includes, but is not limited to, vehicle manufacturers, motorcycle manufacturers, Independent Commercial Importers, other importers, and other holders of EPA emission certificates. This page provides links to these letters based on the year the letter was written.

By clicking on a calendar year link below you will find all the letters that were issued for that year. For more background information about many issues associated with new vehicle and engine compliance, read Advisory Circulars.

This page is maintained by EPA's Office of Transportation and Air Quality (OTAQ).
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