Just call Parts, the battery costs $6.00 you can replace it yourself.
To change key fob battery in 2011 Chrysler 300, simply release the cover by using a screwdriver to take off the battery cover. Then, replace the old battery with a new CR2032 3V/225mAh Lithium coin cell battery. Slide the cover back on and screw the little screw in place.
Will most likely have to consult a Chrysler dealer.
To change the battery in a Chrysler 300 key fob, start by using a small flathead screwdriver to gently pry open the fob along the seam. Once opened, remove the old battery, noting its orientation, and replace it with a new CR2032 battery, ensuring the positive side is facing up. Snap the fob back together securely, and test the key fob to ensure it works properly.
Use your key to unlock the door and then pull the hood release.
Possible weak remote battery or failed remote.
To replace the battery in a Chrysler key, first locate the small slot or notch on the key fob. Use a flathead screwdriver or a similar tool to gently pry open the fob. Once open, remove the old battery, noting its orientation, and replace it with a new battery of the same type, typically a CR2032. Finally, snap the fob back together until it clicks securely.
Use the key??? There are jump start points under the hood.
SwatchBattery has a lot of coin type batteries. http://swatchbattery.com/ . My 2002 300M remote uses a CR2016 (3volt) battery which they carry.
The fob may be defective or it may have lost programming.
The Chrysler 300 key FOB must initially be programmed at the Chrysler dealership. You can use the Chrysler dealership FOB code to change the initial code to your personal code.
There should be a little Phillips screw on one side of the plastic of the key toward the bottom. Just unscrew it and pry it off with your nail and replace the battery with what is in there, it is probably a cr 2032.