i had same problem i got the divertisy unit changed £352 from stealership...all 3 keys work fine now 

just got my quote..£328!!!  ..with 5 years ncb...£60 more than my little 306 1.4cc  :punk:

thanks sandj i will try that tomorrow and let u know the outcome ..thanks again...

hi battery on car is ok.. just tried turning on/off 5 times and pressing buttons and holding them still no joy (next door must think im loopy lol)..  :'(

all 3 have stopped working ..the alarm went off outside the house had to turn it off by putting key in the ignition since then it stopped working on the fob... bmw told me keys only last about 10 years so i will have to order a replacement at £140.....

i got 3 keys with the car and all  working until the other day.. lock switch is working inside the car and door lock opens everything it should...

cheers guys ;D...tried re sync no joy so went to stealership they said i need new key £140 

hi everyone thought id say hello.. brought my x5 2 weeks ago (when out to look at a jag and came back with a x5 3.0i sport lol)..a few probs key fob stopped working yesterday but will look around this site and see what u guys have to say.. :drive: