2002 X5 Key Fob Battery/Replacement

[1bigdog]

Hi all - the batter has finally died. Advice on replacement (not too difficult) or purchase new one. Dealer is expensive. Ebay? thanks!

[mario4705]

the battery for the remote key? you can buy a replacement battery that goes in the back of the key but i doubt you can DIY, or try your luck with a BMW body shop and see what they say? GL

[Qsilver7]

There are lots of DIY threads on replacing the remote key battery in a 9/99-2006 BMW e38/e39/e46/e53...in fact...you can't miss the many videos on YouTube, either.

If you have any soldering skills...you may be able to do it...but do be careful cutting open the new style remote key. Many owners attempting this end up destroying the key by cutting in to deeply and damaging the IC board, or knocking off some of the capacitors and other parts on the board...are cutting the traces to the antenna.

Are you 100% sure that the key's battery is dead? What are your symptoms...and what have you checked? The remote keys have 3 distinct systems that are independent of each other but do work in concert:

1. EWS (immobilizer) - this feature does NOT require the battery inside the key...it is self-powered through induction
2. FZV/FBZV (central locking/remote locking)
3. DWA (anti-theft alarm siren system)

[Crowz]

^ Agreed on making sure its actually dead.

The key part to me is "rechargeable". The battery in these keys is pretty impressive lifespan wise. I have never had a bmw go bad on me battery wise and I have some old ones. Actually I think I have some of the first ones made. The key to keeping it going is charging it.

As little as I drive some of mine I have been thinking of building a stand alone charger but I never get around to it. I have run them down before from non use but it usually just takes a long drive somewhere to get them going again.

Also as mentioned there are a ton of videos on youtube of people changing the batteries.

Do you have more than one key and is it just one key that is "dead"? Usually its a car problem that causes them to stop working as mentioned above.

[THE VEIN]

so how can you tell if the battery is actually dead? im going through this problem right now. pressing the lock/unlock buttons started working less and less of the time till it got to the point its not working at all and im using the key in the door lock

[Qsilver7]

Originally Posted by THE VEIN

so how can you tell if the battery is actually dead? im going through this problem right now. pressing the lock/unlock buttons started working less and less of the time till it got to the point its not working at all and im using the key in the door lock

Key Fob Tester

Call around to your local Autoparts stores (like Autozone, Advanced Auto, O'Reilly's, Pep Boys, etc) and ask if they have a KEY FOB TESTER.

If they don't, then try other local outlets that market batteries...like Batteries Plus. You may also want to check with other vendors that supply services to the automotive market...they may have a key fob tester as a courtesy (Sam's Club tire center, Costco tire center, American Tire, Discount Tire, Firestone, etc).

Example of a key fob tester @ Autozone: customer tests one remote and tester shows it's sending a signal...then they test a new remote and the tester shows no signal

• https://youtu.be/wJvOdTBTH0M
• https://youtu.be/n01KIJadav8
• https://youtu.be/7Wv8Hv4JCr8

[upallnight]

Battery replacement is like brain surgery. If you never done it before, better to take it to a professional or least a guy that knows what he is doing.


https://www.bmwgm5.com/default.htm

[THE VEIN]

so basically if the key starts the car but doesnt lock/unlock the doors using the buttons then its just the battery?

[upallnight]

Originally Posted by THE VEIN

so basically if the key starts the car but doesnt lock/unlock the doors using the buttons then its just the battery?

Yep

[wpoll]

Originally Posted by THE VEIN

so basically if the key starts the car but doesnt lock/unlock the doors using the buttons then its just the battery?

OR... the module in the car has lost sync with the keys. This can be reset by the user (plenty of how-to's on this forum and the 'net).

But it's most likely the battery.