WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes
INTRUSION SENSOR TRANSMITTER
(A645) INTRUSION TRANSMITTER SENSOR SIGNAL SHORTED TO (G945) INTRUSION TRANSMITTER SENSOR GROUND