Diagnose downhill descent control

[ultimatetester]

Yesterday I’ve found out what the fourth button on the lower part of the console is supposed to do. It supposedly activates hill descent control. Unfortunately though, it doesn’t do anything for me. I’ve tried when standing still in both P and D, while cruising, nothing happens.
The internet lacks information around this feature. Can anyone tell me how to diagnose it? The manual says to activate it by pressing the button and then using cruise control to limit the speed further. Unfortunately im already stuck at step 1.

[marvinstockman]

Not to be cute, but isn't the Netherlands kind of flat?

[ultimatetester]

Not to be cute, but isn't the Netherlands kind of flat?

Extremely, but that's why we reach out to the South of France and Austria in the winter where this feature may come in handy! Also I don't like a broken feature...

[marvinstockman]

Try the below site, as it is much more active for the E90:

https://www.e90post.com/forums/forumdisplay.php?f=2