Hyundai Motor America and Kia Motors America will lower fuel economy estimates on about 900,000 cars after an investigation by the U.S. Environmental Protection Agency revealed that the numbers were inflated.
The EPA found that the automakers bumped up fuel efficiency by about one to two miles per gallon on most 2012 and 2013 vehicle models, claiming, for example, that the Hyundai Elantra got 40 mpg on the highway, when EPA tests showed it was actually 38 mpg.
"Consumers rely on the window sticker to help make informed choices about the cars they buy," said Gina McCarthy, assistant administrator for EPA's Office of Air and Radiation in a news release. "EPA's investigation will help protect consumers and ensure a level playing field among automakers."
The automakers in a news release blamed "procedural errors" at their joint testing facility for the faulty numbers and announced they will compensate car owners.
"I sincerely apologize to all affected Hyundai and Kia customers, and I regret these errors occurred," said Dr. W. C. Yang, chief technology officer of Hyundai/Kia research and development in the news release. "Following up on the EPA's audit results, we have taken immediate action to make the necessary rating changes and process corrections."
According to Hyundai and Kia, customers will receive a "personalized debit card that will reimburse them for their difference in the EPA combined fuel economy rating, based on the fuel price in their area and their own actual miles driven."
Also, "as an acknowledgment of the inconvenience this may cause, we will add an extra 15 percent to the reimbursement amount."
Owners can refresh their debit cards for as long as they own the car. In July, Consumer Watchdog and Cuneo Gilbert and LaDuca filed a class action against Hyundai for misleading gas mileage claims in Sacramento County Superior Court in California.