U.S. safety regulators in 2017 launched an investigation into the recall of nearly 1.7 million vehicles by Hyundai and Kia over an engine defect that increases the risk of a crash. The engines involved were fitted in Hyundai Sonata and Santa Fe vehicles in the U.S., and Kia Optima, Sorento and Sportage models, all of which share the powertrain.
A South Korean whistleblower, who was a former quality official at Hyundai, reported concerns in 2016 to NHTSA, which has started probing whether their recalls covered enough vehicles and were conducted in a timely manner.
Hyundai was being investigated by U.S. prosecutors over whether vehicle recalls were conducted properly, Reuters reported in November 2018.