If all 900,000 owners get cards for $88.03, it would cost the automakers more than $79 million a year.
For information, owners can go to www.hyundaimpginfo.com or www.kiampginfo.com .
Sung Hwan Cho, president of Hyundai's U.S. technical center in Michigan, said the EPA requires a complex series of tests that are very sensitive and can have variations that are open to interpretation. The companies did the tests as they were making a large number of changes in their cars designed to improve mileage. The changes, such as direct fuel injection into the cylinders around the pistons, further complicated the tests, Cho said.
"This is just a procedural error," he said. "It is not intended whatsoever."
Krafcik said the companies have fixed testing procedures and are replacing window stickers on cars in dealer inventories. Owners can be confident in their mileage stickers now, he said, adding that Hyundai will still be among the industry leaders in gas mileage even with the revised window stickers.
The mileage was overstated on about one-third of the Hyundais and Kias sold during the three model years, he said.