Mercedes-Benz S-Class 2012 - Manual (Page 351)

hear a continuous warning. This indicates that
you have now reached the minimum distance.
Deactivating/activating PARKTRONIC
:
To deactivate/activate PARKTRONIC
; Indicator lamp
If indicator lamp ; lights up, PARKTRONIC is
deactivated.
i PARKTRONIC is automatically activated
when you turn the SmartKey to position 2
in the ignition lock.
Driving systems
349
Driving and parking
Z