'98 Deville Security System Problem
 

So I was driving home from work last night and the battery symbol popped up along with "Battery Not Charging". I figured I could go one more day (Which I really knew I shouldn't). I'm halfway to work this morning, and the same warning is on, but now "Service Charging System" comes on along with the airbag light, the abs light, and the traction control light. A minute later, the dash lights start dimming and the when I press the throttle, the engine revs but the car doesnt accelerate. I then put it in neutral and coast down the hill to a parking lot. I make it there and it is dead. My boss comes to jump it, and it'll turn over without an issue, but the gear indicator is flashing, and it says "Security System Problem Car May Not Restart".

Battery was new back in October and it registers at 11.9 V on a tester. I pulled all the codes of the panel and they are as follows:
IPC B2750 PASSKey Data Communication Failure
TCS, IPC, ACM U1255 Serial Data Line Malfunction
TCS, PZM C1276 Delivered Torque Signal Circuit Malfunction
RFA U1255 Class 2 Communication Malfunction
MMM U1016 Loss of Class 2 Communication with VCM

Any help would be GREATLY appreciated as this is my only vehicle, and I have no way of getting my son to/from school, nor me to/from work.

As system voltage drops the electronics in the car stop working correctly. Have battery tested to be sure it good. Modern testers can determine if battery will charge or is defective; prior to spending time charging it to find it won't hold a charge. After battery is charged or replaced post if car will start.

I took the battery to the place I bought it and told them it could be bad. They put it in their tester and it tested fine. I also tried putting the battery from my neighbors Impala in it, and it still said and did the same thing unfortunetly. I just took the Caddilac's out and its charging on my work bench at the moment. It was only at 24%. But I figured that the Impala's battery would've work, and that would've told me the battery was the issue.

Would the alternator still cause issues even if a fresh fully charged battery were installed?

Saturday I found out the trunk button on the key fob didn't work, as well as the trunk button on the dash. I didn't drive it all day Sunday. Then come Monday is when the "Battery Not Charging" notice popped up. Would that have anything to do with the issue??

I'm freaking out, as I have no way to work, nor a way to take my son to school. I really hope I can get the issue resolved and quickly

Unfortunately the alternator is computer controlled, and can be a PITA to change out. Did car start with neighbors battery? The alternator could be defective. If you have a voltmeter once battery is charged I would check fuses at fuse boxes to see it if meter reads the same at battery terminals as at fuses. What is condition of battery cables? battery cable that runs from battery to underhood electrical center, under cover on driver's side fender well, could have high resistance.

The car did not start with the neighbors battery. I manually checked all the fuses, and they all passed.

I don't quite follow you about the cable. What should I be looking for on the electrical center one?

I charged the battery, cleared the codes, and the new codes are as follows:
IPC B2750 PASSKey Data Communication Failure
IPC, ACM, TCS, PZM, RFA U1255 Serial Data Line Malfunction
TCS C1276 Delivered Torque Signal Circuit Malfunction
MMM U1016 Loss of Class 2 Communication with VCM

ALRIGHT!!!
I went to remove the PCM and check it over. It all seemed well, and when I replaced it, I figured I'd check the fuses again... I pulled the PCM Battery fuse and sure as sh!t... It was broken almost out of view... I replaced it and the SOB started right up!

BUT........ Now when its running, there is white smoke coming from the exhaust. It never did that before, and I'm hoping it isnt the head gasket. How could that go just sitting there?! It is running fine, no hiccups or rough idling...

Also, the battery still isn't charging, so the alternator must be replaced. That is if the head gasket isn't bad. If so, I'm calling the junkyard to come get this nightmare.

I really appreciate all the help fellas. I'm hoping the gasket is not bad, and I can keep running it till I can afford another vehicle.

A CO test of the cooling system will indicate if head gasket failed