The EPA announced Friday that Hyundai Motor America and Kia Motors America had overstated the fuel economy rating on nearly a million vehicles made from 2011-13.
In a statement issued Friday, Hyundai blamed the discrepancy on "procedural errors" at its testing facility in Korea.
A complete list of affected Hyundai vehicles is here. The list includes the Accent, Elantra, Veloster and Veloster Turbo, Sonata Hybrid, Azera, Genesis, Tucson, and Santa Fe Sport.
Kia vehicles affected are listed here, and include Rio, Sportage, Sorento, Soul and Optima Hybrid.
The Korean automakers, which are effectively siblings, said they will be reimbursing affected customers with a debit card containing the difference between the claimed combined mpg rating and the new EPA rating, based on fuel prices in their area and actual miles driven. These debit cards will be refreshed as long as you own the car. An additional 15% will be added to the reimbursement amount as an acknowledgment by the companies of the "inconvenience" this may cause.
For example, Hyundai says someone who drove 15,000 miles in an Elantra sedan in California during the past 12 months would get a debit card worth $67.05, which includes $8.81 for the inconvenience.
If you owned one of these vehicles but sold it, you're also eligible for a debit card that will be valued based on the same information.
Hyundai said that by accepting one of these cards, customers were in no way agreeing not to pursue other legal action against the company. In July, Santa Monica-based Consumer Watchdog filed a lawsuit against Hyundai over fuel economy claims and is seeking class-action status of the suit.
In addition to reimbursing affected Kia and Hyundai customers, both companies will be issuing corrected window stickers for models already on showroom floors and will adjust the ratings in its advertising.