all doors? or just driver side door? if it doesn't unlock all 4 doors. you might have problem with the key, or the key doesn't communicate with the vehicle. if it doesn't unlock only driver door. have your door checked for door actuator. my e53 key didn't lock/unlock the driver side, it turned out to be the door actuator. my e60 key didn't lock/unlock any door, it was the bad key, i have it replaced for free under warranty. you could buy a new key for $130 from dealer have them reprogram to your car. it will cost you either way since your car is out of warranty. good luck.

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2002 X5 3.0 Siena Red
Premium, Cold Weather, Rear Climate Packages, 19" Wheels
Aluminum Running Boards, Clear Tail Lights, Clear Side Markers
Titanium Kidney Grills, Titanium Trunk Lid, Xenon Headlights
4.6is X5 exhausts, 35% Tint, Aluminum Pedals
2005 530I Mystic Blue
Premium Package, Sport Package, Xenon Headlights
18" Sport Wheels, 35% Tint all around
Mods to come: M-Tech Front Bumper, M5 Side Skirts, M5 Rear Bumper
Quad Exhausts, Style 172 19" Wheels