On certain vehicles, a software problem could cause the vacuum pump to be damaged during engine starting. If this happens, there could be a loss of brake assist. This can cause an increase in brake pedal effort and increase the distance needed to stop the vehicle.
A sudden increase in brake pedal force could lead to an increased stopping distance. This could increase the risk of a crash.
Toyota will notify owners by mail and instruct you to take your vehicle to a dealer to update the engine management software.