The company said it does not yet have a fix, but is working with its supplier on the issue.
DETROITKia is recalling over a half-million vehicles in the USA because the air bags may not work in a crash. Hyundai says the recall now includes all vehicles with the same air bag computers.
NHTSA's investigation remains open, the agency said in a statement Friday afternoon.
"NHTSA's investigation should not have even been necessary", said David Friedman, director of cars and product policy and analysis at Consumers Union, the advocacy division of Consumer Reports. One Forte crash happened in Canada.
In March, NHTSA said it was investigating if other automakers used similar air back control units and if they could pose a risk.
In battle of tweets, Canadas Trudeau dismisses Trump critique
After the conclusion of the summit, Trump again said he would not allow other countries to impose barriers on the United States. Relations between with the United States and the other members, particularly Canada, remained strained on the issue of trade.
No panic in Singapore as summit approaches
The issues on the table remain stubborn and complex for two countries that have been at odds for almost 70 years. Similar scenes were seen on Sunday when Kim and Trump arrived in the city, and when Kim went to meet Lee.