61 13 ... In-Line Plugs, 8-, 12-Pin, System D2.5
WARNING: This page is about a different car, the 2007 BMW 550i and 2006 BMW 550i. However, it is still accessible from the selected car via links, so may be relevant.
Move connector upper section (1) and connector lower section (2) against each other in direction of arrow.
With special tool 61 1 132 (ejector), press back arrester hook (3) of appropriate contact and pull out cable.