So it can either be wiring, a bad ABS module or the pick up ring in the wheel bearing. I would start with what doesn't cost you and check the wiring from the harness side. BBA reman does ABS repairs for around $100 using their eBay sales if they still even offer it there...

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02 Imola on Black Dinan S2 4.6iS
00 RoyalRot on Sand/Black 740i Short Sport