One of my keys stopped working...
 

One of the keys suddenly stoped working, I can start the engin and open doors manualy but non of the buttons work, one in the while lock-unlock button cliks but that's like 1 for 50. x5 3.0 2001, thank you if any body can halp.

you key's battery may be dead, but try this first:

-gather all your keys
-open door, get in, close door
-first key: turn to position 2 in the ignition (on position) five times quickly
-take out key, hold up (unlock) button, and press bmw (lock) button three times
-release, doors will lock and unlock to confirm success
-repeat for each additional key

a replacement key from the dealer will cost about $180-$200

thx. for your advise, I reprogramed one of the keys but the one that was dead is still dead... I think I have to go to the stealer get new one.

Have you been using that key, if not start using it cus if the battery is dead putting it in the ignition charges the key...one of my keys was like that but when i started to use it often it was charged.

About a month or two ago somebody posted a thread, with pics, about taking the key apart and replacing the battery. it didn't look like it was too overly difficult, though it did involve some filing and gluing. But the finished result looked good and worked. I haven't tried it yet, as I do have a dead key (I bought a new key at the dealer last winter), but the battery replacement option is worth a try, as there is nothing to lose.

Bad key
 

It has nothing to do with the bettery. its a key it self.
I got the same problem so I open the key and test the battery and bettery is just fine. The key it self got bad so you will have to order a new one.
Check on ebay for uncut key it much cheeper there since you have onother working key it shound be no problem to reprogram it.

good luck.

i tried this and it doesnt work.... anyone else have same problem?

Got the same problem with mine!

That fix doesn't work.....maybe my key needs replacing!?

the weird thing, i think there's a correlation to me changing my car battery. i think i may have reset something b/c i had the same problem and my dealer kinda fiddled with the key and it worked. i wonder if there is another key sequence that can make it work. the one above is no go...

i got the same problem....i follow the steps, it doesn't work for me....i see the tech at the dealer, he makes it work, however, everytime he does it he closes the doors/windows and i'm actually outside the car so i can't really determine the actual key sequence that he uses