Ford recalling almost 1.5M vehicles in North America file photo.

Transmission problems have prompted a recall of over a million Ford vehicles in North America, including nearly a quarter of a million in Canada.

The Ford Motor Company announced the recall on Wednesday, saying it affects select 2011-2013 Ford F-150 pickup trucks. The company says the trucks with six-speed automatic transmission may experience an intermittent loss of the transmission output speed sensor signal to the powertrain control module, potentially resulting in a temporary, unintended downshift into first gear.

“Depending on vehicle speed, a downshift to first gear without warning could result in a loss of vehicle control, increasing the risk of a crash,” the company said in its recall notice.

Ford said it is aware of five reports of accidents, including one that resulted in a person experiencing whiplash.

The recall affects 1.26 million vehicles in the United States and federalized territories and approximately 221,000 in Canada.

“Affected 2011-13 F-150 vehicles were built at Dearborn Assembly Plant, April 28, 2010 to October 28, 2013, and Kansas City Assembly Plant, May 18, 2010 to November 18, 2013,” Ford said in its recall notice.

Owners of the affected vehicles are advised to contact their dealer to have the powertrain control module software updated.