On Sunday [XXX] and also other times before this, the vehicle will do a fantom breaking. It will slow down, brake, when no other vehicles are near by. On [XXX], the vehicle braked hard while I was in cruise control and traveling on [XXX] near Baldwin, WI. At this time the adaptive cruise control, forward collision warning and brake system warning lights came on. the vehicle was okay to drive the remainder of the way home. I took the vehicle to the Honda dealer on Wednesday February 26th. They reported that they found Code P2583-49 millimeter wave radar fail. They said that they cleared snow debris off front bumper but there was no snow debris on bumper. It was 40 some degrees. I wanted to make you aware of this system problem because the unexpected braking is very hard and could cause an accident if a driver over responds. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)