61 13... Circular connector, 20-pin, system D2.5
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2016 BMW 328i xDrive, 2016 BMW 328d xDrive, 2015 BMW 328i xDrive, 2015 BMW 328d xDrive, and 2014 BMW 328i xDrive. However, it is still accessible from the selected car via links, so may be relevant.
Special tools required:
Carefully press back retaining tabs (1) of internal connector (2).
Turn internal connector (2) until retaining lugs (1) snap into release groove (3).
With special tool 61 0 303 press down retaining hook (4) of corresponding contact and pull out cable.