As a result, the fuel consumption ratings have been increased by an average of 0.3L/100km.
"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.
The two companies will reimburse these customers with a personalized, pre-paid credit card.
''In addition, as an acknowledgement of the inconvenience this may cause, we will add an extra 15% to the reimbursement amount. Current owners will be able to refill their pre-paid credit card at any time for as long as they own the vehicle,'' the statement reads.