commutealot

So the other night, my stock alarm began going off, and there was no way of turning it off...It went off for about a minute, and then stopped for a minute and went off again...for about 30 min. this happened one time before about 6 months ago... I had to disconnect the battery terminal and even after that, the alarm continued for a bit before it stopped all together. Now the display screen says, "Service Theft Alarm" Does anyone know what this is and how to fix it?