Ford has announced a recall of over 600,000 vehicles in Canada and around 4.3 million in the U.S. due to a software problem that could lead to trailer brake malfunctions and issues with exterior lights. The affected models include select years of popular Ford vehicles such as F-150s, Super Duty trucks, Rangers, and Mavericks.

To address the issue, Ford will provide an over-the-air software update for the impacted vehicles. Customers can also opt for mobile service or visit a Ford dealer for the update. The software update is expected to be available for most Canadian vehicles by the end of March and for all vehicles by the end of May.

The software glitch can disrupt communication between the vehicle and a trailer, resulting in non-functional stop lamps and turn signals on the trailer. In some instances, the trailer’s braking capability may also be compromised. The National Highway Traffic Safety Administration has warned that malfunctioning trailer lights or brakes could impair the driver’s control over the trailer, potentially leading to accidents.

Drivers will receive a “Trailer Brake Module Fault” message and notice rapid flashing of the turn signal indicator if their vehicle experiences communication loss with the trailer. Ford has reported 407 incidents possibly linked to the recall issue, but no accidents or injuries have been attributed to it.