Re: ACC/FCW Disabled?
From the owner's manual, page 181:
"If the system turns off, and the EVIC displays “ACC/FCW Unavailable, Vehicle System Error”, there may be a temporary malfunction that limits ACC functionality. Although the vehicle is still drivable under normal conditions, ACC will be temporarily unavailable. If this occurs, try activating ACC again later, following a key cycle. If the problem persists, see your authorized dealer."
It's not that the radar sensor is dirty. That brings up a different error message.