Uber has grounded its fleet of self-driving cars pending an investigation into the crash of an Uber autonomous vehicle in Arizona, a spokesperson for the car-hailing service said Sunday.

No one was seriously injured in the accident which occurred Friday in Tempe, Arizona while the vehicle — a Volvo SUV — was in self-driving mode, the company said.

“We are continuing to look into this incident and can confirm we had no backseat passengers in the vehicle,” the Uber spokesperson said.

The accident occurred when the other vehicle “failed to yield” while making a left turn, Tempe police spokeswoman Josie Montenegros said.

“The vehicles collided causing the autonomous vehicle to roll onto it's side. There were no serious injuries,” she said.

Self-driving Uber vehicles always have a driver who can take over the controls at any time.

Montenegro said it was uncertain whether the Uber driver was controlling the vehicle at the time of the collision.

The company grounded its self-driving vehicles in Arizona after the accident, and then followed up on Saturday pulling them off the road in Pittsburg and San Francisco, the two other locations where it operates self-driving vehicles, the company said.

The car-hailing service has been dented by a series of bad news stories, including disclosures about a culture of sexism, cut-throat workplace tactics and covert use of law enforcement-evading software.

A number of executives have left the company in recent weeks, including president Jeff Jones, as troubles have mounted.

Advocates of self-driving cars say that they can cut down on deadly traffic accidents by eliminating human error. But there have been accidents, including a fatality in Florida in May when a truck struck a speeding Tesla that was on autopilot.

An investigation found no safety-related defects with the autopilot system, but concluded that the driver may have had time to avert the crash if he had been paying closer attention.