The National Highway Traffic Safety Administration has opened an investigation into Tesla after it received two complaints that steering wheels detached in 2023 Model Y vehicles while people were driving.
The preliminary evaluation covers more than 120,000 vehicles, according to an agency filing.
Shares of Tesla closed down 3% Wednesday.
Both incidents occurred at low vehicle mileage.
"Both vehicles were delivered to the owners missing the retaining bolt which attaches the steering wheel to the steering column," the NHTSA said.
The investigation will assess the "scope, frequency, and manufacturing processes associated with this condition," the agency said.
Tesla did not immediately respond to requests for comment.
In one complaint filed with the NHTSA, a driver said he bought his Model Y on Jan. 24, and that the steering wheel fell off while he was driving it with his family in Woodbridge, New Jersey, on Jan. 29.
He said he was "lucky" there was no car behind him and that he was able to pull on to the divider, according to a tweet he included in the complaint.
In a follow-up tweet, the driver said he "lost trust" in Tesla and did not feel safe driving his car home. He later said the Tesla dealership called him and apologized, and the driver shared a photo of a replacement Model Y that he received on Feb. 23.
The investigation into Tesla is a first step before the NHTSA could demand a vehicle recall.