No need to engage in reductio ad absurdum: I never said you knew nothing. Actually I find your posts very informative. It just happened that in this post you made definitive statements on a couple of things which turned out to be inaccurate and I thought it was helpful to point them out.

We all learn from experience, but sometime the First Law of Clarke gets in the way...

Now back on the subject at hand: I was not questioning the fact that the VTG control module monitors oil status. I was questioning the fact that it uses "a sensor measures the resistance of the oil in the transfer case.More parts wear inside,more metal pieces in the oil,resistance decreases."

I've never heard of such sensor, for sure the ATC 700 in my 35d and the ATC 400 in my X3 don't have it and they simply monitored oil indirectly by tracking use and extrapolating the remaining useful life of the oil. Given the very limited gears in the transfer case the primary contaminant of oil comes from the wear of the clutch plates.

The link you posted doesn't mention it nor does any of the BMW literature I have; perhaps you read it elsewhere (hopefully not a forum post )

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