Many 2007 model year trucks (those produced prior to Jan 2007) will in fact have model year 2006 engines which may lawfully be fueled with either 500 ppm highway diesel fuel or 15 ppm highway diesel fuel. We interpret the reference to "model year 2007 vehicles" in our fuel pump labeling and misfueling regulations as referring to those model year 2007 vehicles where either the vehicle or engine is certified to the model year 2007 emissions standards.

Vehicles with engines certified to 2006 model year standards would generally not be using these sulfur sensitive emission control systems. Through amendments made to the vehicle labeling regulations, the fueling of model year 2007 vehicles equipped with model year 2006-certified diesel engines (excluding those engines that certified early to the 2007 standards) with 500 ppm sulfur diesel fuel is permitted, as long as EPA has approved a certificate of conformity applicable to the engine and not the vehicle.

Further, any vehicle with a model year 2007 engine/with an engine that is certified to 2007 model year standards will have a label which states that ULSD must be used. Please see the Clean Diesel Fuel Alliance website (www.clean-diesel.org) to view a letter from EPA to the American Trucking Associations and the Engine Manufacturers Association that addresses this issue.

Question and Answer was originally posted at Questions and Answers on the Clean Diesel Fuel Rules (PDF)(135 pp, 888 K, EPA420-B-06-010, July 2006, About PDF)