Coding the transponder is a completely different thing to coding the key to operate the central locking. There's a guy here in Perth that can make new keys from scratch at about 20% the cost of the dealer. He's an electronics and software engineer so he definitely knows what he's doing. I recently had a complete new key made plus a new battery and circuit board in my old key to keep as a spare for $300. The dealer was going to charge me $950 for just the new key. I'll PM you the guy's details and you can see if he can help you.

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2003 X5 3.0d | 20" Style 168 Wheels | Dice Mediabridge | AE Headlight Upgrade | Invisibulbs All Round | Pioneer 10" Sub in custom enclosure | ECU Remap