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What’s New with HD-OBD

What’s New with HD-OBD

The regulations for heavy duty-onboard diagnostics (HD-OBD) have been updated to include 2018+ alternatively fueled medium-duty vehicles. ROUSH CleanTech is the first propane autogas fuel system manufacturer to receive the Environmental Protection Agency and California Air Resources Board’s HD-OBD certification for all its engines. Until 2018 model year, alternative fuel vehicles were exempt from this certification, but are now held to the same requirements as gasoline vehicles.

Keep in mind that this is an emission regulatory standard that requires new vehicle monitor parameters and reporting. We are ready to meet these regulations with a 50-state certified system for all our vehicle platforms.

What does this mean to you? The check engine light will illuminate for more conditions — most notably evaporative emissions systems. ROUSH CleanTech uses an evaporative emissions system to depressurize fuel rails after shutdown, allowing better vehicle starting and injector life.

Our service manuals have been updated with the new monitored parameters to help you diagnose vehicle issues. They contain helpful descriptions and causes for diagnostics trouble codes related to the fuel system. Be sure to download the latest version at

If you have any questions about HD-OBD, please contact Lance Suttle at