49 CFR §551.46

1. (a)All foreign manufacturers, assemblers, and importers of motor vehicles or motor vehicle equipment (hereinafter referred to as “foreign manufacturers”) must comply with this subpart before offering a motor vehicle or item of motor vehicle equipment for importation into the United States.
2. (b)Unless and until a foreign manufacturer appoints an agent in accordance with the requirements of this subpart, it may not import motor vehicles or motor vehicle equipment into the United States.