I have a 2005 Prius. In the last couple of months or so after I turn off the car, I hear a rather loud noise like a siren lasting for about 10 seconds or more. I wonder what this may be and I would like to know if others have this problem. The car runs fine and I have no other problems. Vembar
Mine is defiantly louder in the harsh cold, but the sound is the same. If yours sounds like a siren then I'd get it checked out.