16 C.F.R. § 309.20 Labeling requirements for new covered vehicles.
(a) Before offering a new covered vehicle for acquisition to consumers, manufacturers shall affix or cause to be affixed, and new vehicle dealers shall maintain or cause to be maintained, fuel economy labels as required by 40 CFR part 600. For dual fueled vehicles, such labels must include driving range information for alternative fuel and gasoline operation and be otherwise consistent with provisions in 40 CFR part 600.
(b) If an aftermarket conversion system is installed on a vehicle by a person other than the manufacturer prior to such vehicle's being acquired by a consumer, the manufacturer shall provide that person with the vehicle's fuel economy label prepared pursuant to 40 CFR part 600 and ensure that new fuel economy vehicle labels are affixed to such vehicles as required by paragraph (a) of this section.