Check another thing off the list then...

I'm left with outlier suggestions. You have rodents that might have damaged harnesses leading to the ECU box in the engine bay? Checked fuses in the 3 different fuse boxes?

Maybe your DME failed? It's not common, but not unheard of either. You could check the electronics box it's housed in for corrosion.

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
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