idk about the controller, but a good and easy way to clear the Haldex is to run a fill of ATF thru it, then drain. Best fluid would be Dexron VI, or just a good Dex III. Skip the friction-modified ATFs, like ATF+4, Universals, HiMiles, etc. Dex is nice and grippy for the clutchpacks, to compensate for the slick Gear Oil (GL-5) that's in there.
fwiw, if you were just flushing an overdue Haldex or for some reason needed a replacement fluid in an emergency, a "Universal" or "Multi" ATF has special friction additives which react "properly" to the clutch material they are exposed to.
Whatever you do, imo that GL-5 has to get out, and ATF is the most cost-effective way to do it.