The support provided by the system can beimpaired if:
Rthere is poor visibility, e.g. due to insuffi-cient illumination of the road, or due tosnow, rain, fog or heavy spray
Rthere is glare, e.g. from oncoming traffic,the sun or reflection from other vehicles(e.g. if the road surface is wet)
Rthe windshield is dirty, fogged up, damagedor covered, for instance by a sticker, in thevicinity of the camera
Rthere are no lane markings, or severalunclear lane markings are present, e.g.around construction sites
Rthe lane markings are worn away, dark orcovered up, e.g. by dirt or snow
Rthe distance to the vehicle in front is tooshort and thus the lane markings cannot bedetected
Rthe lane markings change quickly, e.g. lanesbranch off, cross one another or merge
Rthe road is narrow and winding
Rthere are highly variable shade conditionson the roadway
The system is switched to passive and no lon-ger assists you by performing steering inter-ventions if:
Ryou actively change lanes
Ryou switch on the turn signal
Ryou take your hands off the steering wheelor do not steer for a prolonged period oftime
iAfter you have finished changing lanes,Active Steering Assist is automatically activeonce more.
Active Steering Assist cannot provide assis-tance:
Ron very sharp corners
Rwhen a loss of tire pressure or a defectivetire has been detected and displayed
Observe the important safety notes on ActiveDistance Assist DISTRONIC (Ypage 156).
The steering interventions are carried out witha limited steering moment. The systemrequires the driver to keep his hands on thesteering wheel and to steer himself.
If you do not steer yourself or if you take yourhands off the steering wheel for a prolongedperiod of time, the system will first alert youwith a visual warning. A steering wheel symbol
appears in the multifunction display. If youhave still not started to steer and have nottaken hold of the steering wheel after five sec-onds at the latest, a warning tone also soundsto remind you to take control of the vehicle.Active Steering Assist is then switched to pas-sive. Active Distance Assist DISTRONICremains active.
Activating Active Steering Assist
XSelect the Active Distance AssistDISTRONIC with Active Steering Assist func-tion using the on-board computer(Ypage 198).TheActive Steering Assist OnActive Steering Assist Onmes-sage appears in the multifunction display.Active Steering Assist is activated.
Information in the multifunction display
If Active Steering Assist is activated but notready for a steering intervention, steeringwheel symbol Cappears in gray. If the sys-tem provides you with support by means ofsteering interventions, symbol Cis shown ingreen.
Deactivating Active Steering Assist
XDeactivate the Active Distance AssistDISTRONIC with Active Steering Assist func-tion using the on-board computer(Ypage 198).TheActive Steering Assist OffActive Steering Assist Offmes-sage appears in the multifunction display.Active Steering Assist is deactivated.
When Active Distance Assist DISTRONIC isdeactivated or not available, Active SteeringAssist is deactivated automatically.
164Driving systems
Driving and parking