BMW Keys. Is there a battery?
 

Does anyone know if the BMW keys (the E53) style have batteries inside them that can be easily changed? All of the remote functions on one of my two keys doesn't work. Is this an easy fix?

there is a battery which is rechargable and it recharges when it is in the ignition.

Any idea how long it takes to recharge and in what position the key must be in? I've used the key on drives and it is still dead.

Quote from Service manual:

FZV Key Rechargeable Battery

From KL R, the battery inside the key head is charged inductively by the EWS ring antenna via a coil antenna integrated in the key. The charging process is controlled by electronic circuitry integrated in the key.
• The service life of a radio-control key used under normal conditions corresponds to the vehicle lifespan.
• If the FZV keys are not used (ie: stored in a drawer), the battery will be discharged after approx. 1.5 years.
• The time required to fully charge a discharged battery is approx. 30 hours.
• The remote control can be operated about 15 times after a charging period of approx. 30 minutes (driving time).

Hi,

I think u need to activate the key after the battery becomes dead. I believe 1 hr should be fine to charge the key.

Here is what I found about initializing additional keys.

1. Enter the vehicle and close the doors
2. Briefly turn the ignition on and off (5 times within 5 seconds).
3. Remove the key; press and hold unlock. While holding unlock rapidly press lock button 3 times within a period of 10 seconds.
4. Release unlock button.
5. The central locking system activates and releases all locks in rapid succession to indicate that the initialization has been successful.
6. To initialize additional remote control keys (make sure that no more then 30 second elapse between each initialization procedure) repeat steps 3 and 4.


You have to do it for all keys, otherwise others will be deactivated.

Hope this works for you.

Hey eyeiieye-
AWESOME advice! Worked PERFECTLY. A+++ to you my friend.

So to sum up, charge the key for about 1 hour, though I left mine in overnight. And then run the initialization procedure as follows:

1. Enter the vehicle and close the doors
2. Briefly turn the ignition on and off (5 times within 5 seconds). Don't actually turn on the car.
3. Remove the key; press and hold unlock. While holding unlock rapidly press lock button 3 times within a period of 10 seconds.
4. Release unlock button.
5. The central locking system activates and releases all locks in rapid succession to indicate that the initialization has been successful.
6. To initialize additional remote control keys (make sure that no more then 30 second elapse between each initialization procedure) repeat steps 3 and 4 ONLY. Do not repeat step 2. Note that you MUST initialize all the keys (at least that is what I found, otherwise by initializing one you de-initialize the others).

I have one thats completely dead. Won't even start the car. None of the methods above worked. Is there any way to charge the key without having the engine on?

you need to have dealer re-code it ,cuz, your car not reconize it

My mom had one of these keys get fried in her 7 series when she was trying to jump start me in my old Montero. We didn't follow the owner's manual completely and it wiped all the information off the key.

But i think the fact that it charges itself is awesome.

My key only seems to work though at a distance of 15 feet or less, is everybody else's about the same?

If the battery is actually dead somebody did a piece on here a while back about replacing the battery in the key. I think it was last year but a search should pull it up.