Ford Motor has recalled about 238,000 Explorers because of a defect that poses a risk of the sport utility vehicles rolling away if the parking brake is not engaged.

The affected models, from 2020 through 2022, have been discontinued.

“The rear axle horizontal mounting bolt may fracture and cause the drive shaft to disconnect,” the National Highway Traffic Safety Administration said in a letter to Ford on Thursday.

If the shaft, a rod that transfers power to the wheels and makes the vehicle move, disconnects, it could result in a loss of drive power or a vehicle rollaway if the parking brake is not applied, the letter said.

“Either of these scenarios can increase the risk of a crash,” Alex Ansley, the chief of the recall management division for National Highway Traffic Safety Administration, wrote.

A Ford spokeswoman said in a statement that the “risk of rollaway park was addressed with a software update in previous recalls.”

The difference with the latest recall is the remedy — now Ford is required to inspect all 230,000-plus vehicles. Previously, it was only inspecting a vehicle if it experienced failure and then replacing the parts free.

In a previous related recall, Ford was aware of 396 reports of rear axle bolt failures, less than 5 percent of which resulted in a roll-in-park or loss of power condition, the statement said.

Letters notifying owners of the recent recall are expected to be mailed Nov. 6. Drivers can also see if their vehicle has been recalled by entering their Vehicle Identification Number or the year and model of the car on Ford’s website.

Ford said it was not aware of any accidents or injuries related to the defect, according to agency documents.

Vehicle recalls have become more common in the United States over the last two decades or so, according to a 2019 report by McKinsey & Company.

In 2016, the U.S. auto industry reached more than 1,000 vehicle recalls for the first time. In 2017, an average of about three vehicles were recalled for every vehicle sold, according to the report.

In 2022, Ford recalled 2.9 million vehicles, including 1.7 million Ford Escape S.U.V.s, because of a potential defect that could let them move even with the gear shift seemingly in the park position.

In September, regulators flagged 52 million airbag inflaters used by dozens of carmakers as being susceptible to rupture.

Since 2015, recalls typically have been related to airbags, according to the McKinsey report. However, as vehicles are made with more complex features, there has been an increase in recalls for software and electronic problems.