Sorry to hear of your problem, you didn't say what year you have but a few have had trouble with the siren internal batteries corroding and that causing problems. I would replace the siren if it is over 6 years old and go from there. The batteries in the fob will not cause the siren to go off, could you have accidentially set it off with something in your pocket hitting the button? Best advice I can offer is not to take it back to the dealer or your going to need a lot of moey.