Mercedes-Benz GLE 2015 Owner's Manual page 230

This indicates that you have now reached the
minimum distance.
Deactivating/activating PARKTRONIC
Indicator lamp
:
To deactivate/activate PARKTRONIC
;
If indicator lamp : lights up, PARKTRONIC is
deactivated. Active Parking Assist is then also
deactivated.
i
PARKTRONIC is automatically activated
when you turn the key to position 2 in the
ignition lock.
Driving systems
227
Z