Was driving with AutoPilot today and received the big red steering wheel and a message to take over immediatly which I did. I didn't see any reason for TACC or Autosteer to be confused so I tried turning it back on. I got an error that started "cruise not available reduced front radar visability". I couldn't turn TACC back on for about fifteen minutes. Then suddenly the TACC and Autosteer icons reapeared. Any ideas? Why would visability be reduced?