Message on CD player display showing, remote control battery low and anti theft system not working

There could be a problem with the Anti-Theft Control Unit box.
The remote control battery low message is probbly just an symptom of the theft module failure. You may find that the door locks stop working, windows, etc. And other sytems tied intot the anti-theft system.
You can run an OBD code check and see if it comes back as a fail theft module code.

Best to get alarm codes read with a tech2, this is the first I have heard of issues like that even with you changing the remote keyfob battery and it still shows same message on info display [S.I.D], did u check if the floor carpeting is wet under your drivers seat, cause there is a unit under the seat below the carpet thats a part of the alarm system & key function, does your alarm go off at anytime?