Why is the key fob not working after flat battery?

If you have the original manufacturer FOB, most build a spare emergency key INTO the FOB. Investigate it and see if there's a compartment you didn't notice before. Some can be accessed through a tiny hole on the FOB. Once you have the metal key, use it in the door lock to open the door.

flat fob key batteries will be half the problem. Because the immobiliser cannot read the fob keys it probably put the system into anti theft mode as well. Replace the fob key batteries and if it still will not start, some systems will reset by using a scanner .

battery may be flat in the fob or the vehicle has forgotten the code for the fob. and will need resetting. change the battery use the key to open the door put key in the ignition. ( fob Ir old type leave fob off the key) turn to number 2 and press fob till doors lock and unlock. then its reset. dont be worried if the alarm goes off while doing this it will go off when the code is restored. if you have 2 fobs you will need to rest that one to.

This model year comes equipped with Keyless Enter-N-Go, which uses an electronic transmitter in the key fob to communicate with the car. The vehicle's doors will not unlock and the vehicle will not start if the key fob is not matched to the vehicle or if the commonly-available watch battery in the key fob has been depleted. The EVIC will flash a message upon vehicle startup if it determines that the battery in your key fob is low on charge and should be replaced.

To open the doors, try the following:

1. Use the spare key fob that came with the vehicle. If the battery in your main key fob is depleted, the spare key fob's battery may still retain charge due to its much more occasional use.

2. The key fob comes with an emergency key inside of it. To remove the emergency key, slide the mechanical latch on the back of the key fob sideways with your thumb and then pull the key out with your other hand. This key will allow you to unlock the driver's side door and glove compartment. It will not start the vehicle.

To start the car with a severely-depleted key fob battery, try the following:

1. In case the ignition switch does not change with the push of a button, the RKE transmitter (Key Fob) may have a low or dead battery. In this situation a back-up method can be used to operate the ignition switch. Put the nose side (side opposite of the emergency key) of the Key Fob against the ENGINE START/STOP button and push to operate the ignition switch.

To replace the battery in your key fob, try the following:

1. Remove the emergency key from the key fob following the directions above.

2. Using a vinyl spudger tool or a flat-bladed screwdriver, gently pry the two halves of the key fob apart at the indented slot above the slot for the emergency key.

3. Replace the depleted battery with a new battery. Use the depleted battery to visually match the size. The battery is usually available wherever watch or hearing-aid batteries are sold.

4. Snap the key fob back together and replace the emergency key. If the issue is a depleted battery, your key fob should operate normally.

If the issue is not related to the state of the battery, you will probably need to contact your local dealer for service.

Source: Owner's Manual, pages 12-17

http://justgivemethedamnmanual.com/dodge/dodge-charger-owners-manual/

Duplicate question

I just figured out how to change the battery in the Advanced (keyless) fob for my 2010 Mazda CX9. You just need to take out the physical key, and use a small flat-head screwdriver to pop off the back cover. Then there is a black battery cover with an o-ring that just pulls up to reveal the CR-2032 Battery. Here are some pictures to explain better:

depending on the type of security system, it is sometimes necessary to re-sync the keyfob to the car after a flat battery on the car or the fob.
this is normally just a matter of turning the key to the IGN position and pressing the button on the key fob. you may have to hold the button for a second or two but this will normally re-sync the system.

if it does not work then you will have to sent more detailed information on the security system. ie factory fitted or aftermarket system with make and type (normally found on the siren unit under the bonnet.

hope this helps

Hi, You need to separate the fob part from the key. This is done by using a flat head screwdriver in the slot provided. The slot is mid way on the track that the key folds into. Once you have the key split the fob can then be split , the battery is inside.

hi, this message is warning you that the battery in the key fob is going flat if this battery goes totally flat you wont be able to start your car as its this signal from the key fob that turns the imobiliser off so with out this fob your car wont start so its best you get the battery changed sooner rather than later.

Let me know how you get on or if you need further assistance ok

start the engine and then turn off and lock ur steering and it will work