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On-Board Diagnostics (OBD)

OBD Logo - Check Engine Light General Resources

This page features links to a variety of general resources on OBD, organized into the following categories:

Screen Shot of EPA Outreach Kit Materials
Screen Shot of EPA Outreach Kit Materials
Screen Shot of EPA Outreach Kit Materials
Screen Shot of EPA Outreach Kit Materials

EPA Fact Sheets

Other Fact Sheets exit EPA

NOTE: You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.

  • On-Board Diagnostics: A New Generation of Motor Vehicles
    Developed by New Hampshire, this fact sheet describes OBD, including how it works, its benefits, new testing requirements, and how to service OBD-related problems.
  • Fact Sheet: On-Board Diagnostics (PDF) (101K)
    This fact sheet, developed by the Oregon Department of Environmental Quality, includes general background on the state's OBD testing program, as well as the link between OBD and cleaner air.
  • Facts About On-Board Diagnostic II Systems
    This fact sheet, developed by the California Air Resources Board, includes general information about OBD in a simple question-and-answer format.
  • Understanding On-Board Diagnostics
    This fact sheet, developed by the Illinois Environmental Protection Agency's Air Team, describes the OBD system, how it works, its relation to vehicle emissions, and the basics of the OBD check.

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