Mercedes-Benz V-Class 2021 Owner's Manual page 188

* NOTE Damage when uncoupling in a
state of overrun
Uncoupling in a state of overrun can damage
the vehicle.
Do not uncouple trailers with an
#
engaged overrun brake.
Shift the transmission to position j.
#
Apply the vehicle's parking brake.
#
Close all the doors.
#
Apply the trailer's parking brake.
#
Further secure the trailer against rolling away
#
with a wheel chock or similar object.
Remove the trailer cables and safety chains.
#
Uncouple the trailer.
#
Driving and parking 185