On-Board Diagnostics (OBD)
Do you drive a 1996 or newer car or light truck? If so, it is equipped with OBDan advanced "on-board" computer system responsible for monitoring your vehicle's engine, transmission, and emissions control components. If your "Check Engine" light comes on and stays on, your OBD system is telling you that it has detected a problem with your vehicle. In addition to protecting the environment, this light, and the OBD system behind it, can save you time and money by identifying minor problems before they become major repair bills.
OBD also plays a key role in nearly 30 state and local vehicle emissions testing programs around the country. In these areas, technicians use OBD checks to identify vehicles that are in need of repair and therefore are exceeding emissions standards. As a result, OBD serves as an important tool in improving air quality and helping states meet national air quality standards.
Use the links below to learn more about OBD and its benefits to you:
- Benefits of OBD
Review the many benefits of your vehicle's OBD system.
- Car Care What You Can Do
Discover the important role OBD plays in responsible car care and learn other ways you can maintain your vehicle and reduce its emissions.
- Information on Manufacturer Emissions Warranties for 1995 and Newer Cars and Trucks (PDF) (10 pp, 607K, EPA-420-F-15-035, October 2015, About PDF)
If you own a 1995 or newer car or truck, vehicle manufacturers are required by federal law to provide warranty coverage for certain components of your vehicle's emissions-control system. To learn more, review some frequently asked questions about emissions warranties.
- Frequent Questions
Learn more about OBD by reviewing a list of frequently asked questions.
- Additional Information
Review additional information about OBD, including fact sheets and brochures.