Paccar is recalling more than 56,000 Kenworth and Peterbilt trucks due to a potential software glitch that could cause lift axles to raise or lower unexpectedly, and may lead to delayed or erratic activation of headlights and brake lights.

The recall affects certain 2023-2026 Kenworth T380, T680, T880, Peterbilt 520, 548, 567, 579, 2024-2026 Kenworth T480, W990, Peterbilt 536, 537, 589, 2025 Kenworth T180, Peterbilt 535, 2025-2026 Kenworth T280 and L770 vehicles. 

Because of a software problem on some of these trucks, the tail brake light, upper and lower beam headlights, reverse light, and turn signal may not illuminate as intended. 

In addition, the lift axles, if lowered, may revert to a raised position, or oscillate up and down when the signal warning lights are activated. 

These issues may result in non-compliance with FMVSS/CMVSS 108. 

The National Highway Transportation Safety Administration, in its recall notification, pointed out the safety issues cause by the glitch:

• Delayed and unsteady illumination of vehicle stop lamps and un-commanded change in headlamp illumination may increase the risk of crash. 

• Un-commanded position change of lift axles may increase the risk of injury. 

Drivers won't get any warning of the problem, although they may see the change in forward lighting activation as it occurs.

What's Causing the Erratic Lighting and Lift Axle Behavior on Some Paccar Trucks?

The vehicle controller software has an incorrectly configured time counter that may cause some specific messages from the vehicle ECU to the chassis module to not be sent at their intended frequency. 

Dealers will update the vehicle software, free of charge. The manufacturer has not yet provided a schedule for recall notification. Owners may contact Kenworth's customer service at 1-425-828-5888 and Peterbilt's customer service at 1-940-591-4220. Paccar's number for this recall is 25PACF.