Technical Description (Comment)
WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.
The theft-alarm horn is shared by the keyless entry system. If the theft-alarm horn sounds normally through the keyless entry system answerback, the ETACS-ECU may be defective.