Hello, This morning out of the blue this error came on while I started the car. Shutter is closed when I checked. I did found two small stones. One of them was stuck at the bottom and I could definitely tell it could prevent the shutter from opening. I managed to get the stones out.. but the "Grille Shutter Inoperative" message won't go away. CEL is still on as well. Is it normal that it will stay on for some time??