What happened

Ford announced a recall of approximately 4,380,609 vehicles in the U.S. across several popular model lines, including the F-150, F-250 Super Duty, Maverick, Ranger, and Expedition), from model years 2021–2026. 

The problem was a software glitch in the Integrated Trailer Module (ITRM) that causes a loss of communication between the towing vehicle and the trailer, typically occurring during the initial power-up or when the vehicle exits "sleep mode." 

The failure can lead to the total loss of trailer stop lamps, turn signals, and, in high-series models, the complete loss of trailer brake functionality. 

While Ford reported 407 related warranty claims, no accidents or injuries have been officially confirmed at the time of the announcement. 

Why it happened

The root cause is a software vulnerability in the ITRM in which a timing conflict ("race condition") between the ITRM and a control component called the CAN Standby Control bit occurs during power-up, causing the module to activate in a non-communicative state.