Do you have the servo assisted brakes?
On my 2005 K12s I was able to revive my ABS, removed the pump and then removed the 2 servo motors, full cleaning of the motors with brake clean, also reversed the polarity of the motors on the bench and ran them in reverse of their normal rotation. I also found that the push on connectors that power the servo motors was very loose, I pinched down the push on female spades and they were significantly tighter. Reassembled and replaced, all worked again (my original problem was the rear servo motor would only work sporadically at best.
One other interesting thing, the dealer said they completely flushed the system to see if that would get the pump going, when I flushed and bled I was still getting quite a bit of darker brown fluid out.
Hopefully that helps you out if we have the same pumps...