U.S. safety regulators are investigating complaints of brake problems on Hyundai Genesis full-size luxury cars.
The National Highway Traffic Safety Administration says the probe affects about 40,000 cars from the 2009 model year.
The agency has received 23 complaints of that drivers had to push harder than normal on the brake pedal to make the car stop. One driver crashed into a stopped vehicle while another had to use the emergency brake to stop, sending the car into a spin.
No injuries have been reported. Several complaints alleged that the problem was traced to a faulty antilock brake computer.
The investigation will determine if the problem is big enough to cause a recall.
It's the first investigation since the 16-day partial government shutdown began on Oct. 1.