On certain trucks, a software problem could cause the brake lights not to work when the brakes are automatically applied during emergency braking.
Safety Risk
Brake lights that don't work could cause others not to recognize when a vehicle is braking. This could increase the risk of a crash.
Corrective Actions
Daimler Truck North America (DTNA) will notify owners by mail and advise you to take your truck to a DTNA authorized service facility to update the active brake assist (ABA) software.