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On-Board Diagnostics (OBD)

Facts and Figures

Today's Vehicles Impact Air Quality
  • The current fleet of more than 200 million vehicles driving on U.S. highways is a major source of air pollution, accounting for approximately 77 percent of the carbon monoxide and 45 percent of the nitrogen oxides in our nation's air. If not properly maintained, these vehicles will not perform as originally designed, causing them to work harder, wear out faster, and pollute more.
  • The number of vehicles in the United States is increasing twice as fast as the population growth.
More and More Vehicles Use OBD Technology
  • OBD is available in all model year 1996 and newer light cars and trucks.
  • More than half the vehicles on the road today are OBD-equipped.
OBD Provides Accurate Diagnosis That Leads to Effective, Durable Repairs
  • OBD is sensitive enough to detect pinhole-sized leaks in the fuel system or gas cap.
  • OBD technology is faster and more powerful than a space shuttle's navigation computer.
OBD Checks Are an Effective Emissions Control Strategy
  • Existing OBD I/M programs have successfully tested millions of vehicles.
  • OBD checks at centralized stations are being completed in five minutes or less.
  • OBD fail rates currently average less than 3 percent.
  • The average repair cost for OBD-failed vehicles is comparable to costs for the most rigorous tailpipe tests.

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