I changed mine out after 200000km, it was an easy fix, left me stranded in another country, (Wa state) but i was able to walk back to Canada (i live 5 blocks from the USA border in Lynden Wa) grab my trusty Jeep, picked up a new one (ouch!!) and grabbed some tools, and off i went. My dead giveaway was no whirring sound on start up, and cyl 1 misfire with fuel cut off codes. checked fuses, and its def a fuel pump! changed it out in about 10 min, trickiest part was getting the back seat to stay up when i was pulling out the pump! at least my fuel tank was pretty low (light was on) so the pump wasnt dripping with fuel all over my seats, none the less, i put a few clean rags down to catch any potential fuel drips!
it was a pretty simple re and re, just an inopportune time and location of the breakdown! i wont run my X5 down to empty anymore! when the light comes on, i take it as my call to get fuel at the next exit!

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2003 X5 3.0i (02/2003) sport package, Sapphire black metallic / Black Dakota Sport seats. compass mirror retrofit, trailer hitch retrofit, Prodigy P2 trailer brake controller installed, PDC retrofit, Lumbar support retrofit. heated rear seats retrofitted. Running boards retrofitted and subwoofer install in progress. 4.8is Brakes installed front and back. Bluetooth TCU installed, Rear Fog lights installed. Retrofitted reclining rear seat backs.