US auto safety regulators have opened an investigation into Tesla’s Model Y SUV after getting two complaints that the steering wheels can come off while being driven.

The National Highway Traffic Safety Administration says the probe covers an estimated 120,000 vehicles from the 2023 model year.

The agency says in both cases the Model Ys were delivered to customers with a missing bolt that holds the wheel to the steering column. A friction fit held the steering wheels on, but they separated when force was exerted while the SUVs were being driven.

The agency says in documents posted on its website Wednesday that both incidents happened while the SUVs had low mileage on them.

In one complaint filed with NHTSA, an owner said he was driving with his family on Route 1 in Woodbridge, New Jersey, when the steering wheel suddenly came off on January 29, five days after the vehicle was purchased. The owner wrote that there were no cars behind him, and he was able to pull toward the road divider. There were no injuries.

“It was horrible experience, I was driving back from mall with family and in middle of freeway steering wheel fell off,” said Prerak Patel. “I was on left lane when this happened, I can’t move my car to left or right. “However I was lucky that road was straight and able to stop my car at the divider.”

Messages were left seeking comment from Tesla, which has disbanded its media relations department.

At first, a Tesla service centre gave Patel a cost estimate of $103.96 to repair the problem. The service centre apologised in what appeared to be text messages posted on Twitter.

When Patel wrote that he had lost faith in Tesla and asked for a refund, the service centre removed the charge and wrote that Tesla doesn’t have a return policy, but he could reach out to the sales and delivery team.

He said that Patel was later given the option of keeping the car or getting it replaced with a new one, and Patel chose to do so.

Tesla Model Y electric cars stand at the new Tesla Gigafactory electric car manufacturing plant near Gruenheide, Germany. Photo / Getty Images

Patel said he’s a fan of Tesla CEO Elon Musk and has invested a large chunk of his savings in the stock, which fell 3 per cent.

“My kids were a little scared to ride in a loaner Tesla and, as a parent, we are able to restore their confidence,” Patel said. “My family is fine now and hope Tesla will investigate and improve its [quality control] so no other family experience what we experienced.”

Detached steering wheels are rare in the auto industry, but not unprecedented. In February, Nissan recalled about 1000 Ariya electric vehicles because the wheels could come off the steering column due to a loose bolt.

Yet the latest NHTSA investigation adds to a long string of problems that Tesla is having with the US road safety agency. In the past three years, it has opened investigations of Tesla’s “Autopilot” driver-assist system crashing into parked emergency vehicles, and problems with suspensions. At least 14 Teslas have crashed into emergency vehicles while using the Autopilot system.

The same day the report was aired on problematic Tesla steering wheels, US safety regulators said a Tesla that crashed into a firetruck in California last month killing the driver and injuring a passenger, as well as four firefighters, is suspected of operating on one of the company’s automated driving systems.

In February, NHTSA pressured Tesla into recalling nearly 363,000 vehicles with “Full Self-Driving” software because the system can break traffic laws. The system, which cannot drive itself, is being tested on public roads by as many as 400,000 Tesla owners. But NHTSA said in documents that it can make unsafe actions such as travelling straight through an intersection while in a turn-only lane, going through a yellow traffic light without proper caution or failing to respond to changes in posted speed limits.

The US Justice Department also has asked Tesla for documents from Tesla about “Full Self-Driving” and Autopilot.

The agency also is investigating complaints that Teslas can brake suddenly for no reason.

NHTSA has sent investigators to 35 Tesla crashes in which automated systems are suspected of being used. Nineteen people died in those crashes, including two motorcyclists.

Since January of 2022, Tesla has issued 20 recalls, including several that NHTSA required. The recalls include one from January of last year for “Full Self-Driving” vehicles being programmed to run stop signs at slow speeds.

- Tom Krishner and Michelle Chapman, AP