Alarm started sounding after car had sat for about 20 hours in the garage. It was unlocked and all doors were fully closed. Could only get it turned off by putting the key in the ignition and clicking one position. Upon key removal, the alarm would start up again. My remote was having no effect, but then I determined the battery was dead.
After replacing the remote battery and locking and unlocking the car with the remote I was able to remove the key without the alarm sounding. I have had dead remotes before, but never with the alarm issue. Any thoughts on what caused this?

 

Any chance the Panic button was stuck?

 

A dirty contact pad, low fob battery voltage, low car battery voltage. This happened to me with Oldblue, the car battery had 2 dead cells. The computer didn’t like that!

 

Was the fob in your pocket?

 

Panic button hadn't been touched and the remote was sitting in the bowl where we keep the car keys. Car battery is getting up there, but has given no indication of any weakness. As far as the remote, the battery was low (just under 3 volts) but the pads look nice and clean. I'll check what the static voltage is on the car battery. Thanks for the ideas
12.2 volts from the battery terminals directly

 

12.4 volts or less is a dead or at least dying battery

 

OK, thanks Blue. Just looked up and its over 7 years, not bad for a walmart battery

 

Gambler are you? Go out and buy a power ball ticket, luck be a lady tonight!

 

Panic button not touched was not the question, "was it stuck ?" was.
In a bowl with other keys. Not possible that the panic button got hit?
Dead battery usually beeps the horn 1 time then locks the doors and captures a key if in the ignition.
Any chance any of the doors or hatch or hood was not fully latched? Could one of the door switches be stuck open.
The only thing that should set the alarm off is opening a door, hatch or hood after being locked with the fob or being otherwise armed.
The only input is from the door/hatch ajar switches and the hood ajar switch (if equipped with remote start). The panic button causes the same actions as a content theft deterrent {horn honking and turn signals flashing).

 

Panic button was not stuck and neither set of keys had been touched in over 20 hours. I also had also checked all doors, gate and hood. Man have battery prices gone up in the last 7 years!