Not sure if the 3.0l is the same as the 4.8l, BUT the 4.8l WILL NOT indicate if you have a charging problem!!! I have an UltraGauge set up in my '08 4.8l X5 because my alternator is currently flaky and I have been "managing" the problem until the weather gets a bit warmer.
When the charging Voltage drops, then you start having all sorts of strange problems with system faults popping up due to sub module communication problems.
See my comments here -
http://www.xoutpost.com/bmw-sav-foru...tem-issue.html