I have a 2006 CS and for the last few weeks I've noticed a beeping sound coming from the cabin. It's a low beeping tone that goes for about 10 seconds then goes away. It'll come on again and off again for about 5 minutes then it's off until I start it again. Sometimes it even comes on as soon as I open the door. There's no warning lights on the dash, but it does say service now. Is that the cause for the beeping noise? I don't see anything abnormal with the car and drives fine.