Your engine battery is probably the culprit. I had the same thing happen and that was the cause. It gets worse though - if you leave the vehicle without locking it and battery drops more, the machine locks everything and you can't get in! Key won't work, nothing!

I had that happen and had to have it towed to a Chrysler dealer. They went crazy trying to figure it all out. I put the biggest honking battery in it I could find. Like a previous poster said, there 5 years old now.