On January 9, 2015, the U.S. District Court for the District of Columbia approved a proposed consent decree that had been negotiated by EPA and the California Air Resources Board (CARB) that resolved the government's claims that Hyundai Motor Company, Hyundai Motor America, Kia Motors Corporation, Kia Motors America, and Hyundai America Technical Center, Inc. violated the Clean Air Act and the California Health & Safety Code by falsifying fuel economy and greenhouse gas emissions claims that affected more than 1 million vehicles sold in the 2012 and 2013 model years.

It was alleged in the consent decree that there was a discrepancy in the information provided by the defendants in connection with the application for "Certificates of Conformity" and the actual specifications of the vehicles in that the vehicles provided lower fuel economy and emitted higher emissions than was stated in the applications. 126,000 vehicles were sold in California, and the $100,000,000 civil penalty--the largest yet recovered--was split between the U.S. Government ($93,700,000) and the State of California ($6,300,000). In addition, Hyundai agreed to forfeit 4.75 million greenhouse gas credits.

The proposed settlement was published in the Federal Register, and several comments were received. Some of the commenters requested that Hyundai also provide $25 million of Supplemental Environment Projects in some states, but the United States rejected this request, arguing that to do so would unravel the settlement that had been negotiated. The decision is reported as United States of America, et al. v. Hyundai Motor Company, et al.