One annoying thing I have found also is that I have a very steep driveway. Well, the oil level sensor will set itself when the vehicle starts, not while it's running. So then after I drive somewhere and park on the flat, when I start the car the next time, then I get a true reading of the oil level.

The sensor seems to check the oil level at start and then only after an hour or so of driving which has caught me off guard a couple of times when I have left for a long trip, thinking everything was good to go and either get an hour away or stop at a rest area and then the warning comes up to fill with oil.

I have the 35d and the two times it has been an issue is long trips 8-10 hours when I have been running 80-90 mph for a couple of hours, so not entirely surprised and it's also been close to the oil change interval. But now has me carrying a spare quart of oil so I don't get caught off guard again.