Active Lane Keeping Assist monitors the area in front of your vehicle by means of the multifunction camera More. It serves to protect you against unintentionally leaving your lane. You will be warned by vibration pulses in the steering wheel and guided by a course-correcting brake application back into your lane.
Active Lane Keeping Assist is available in the speed range between 60 km/h and 200 km/h.
Active Lane Keeping Assist can neither reduce the risk of an accident if you fail to adapt your driving style nor override the laws of physics. It cannot take into account road, weather or traffic conditions. Active Lane Keeping Assist is only an aid. You are responsible for maintaining a safe distance to the vehicle in front, for vehicle speed, for braking in good time and for staying in lane.
If a lane-correcting brake application occurs, display 
appears in the multifunction display.
The system does not intervene if you activate the turn signal indicator.
Vehicles with Driving Assistance Package: if the system detects an obstacle, such as another vehicle in the adjacent lane, it will intervene regardless of the turn signal indicator.
Active Lane Keeping Assist detects a lane marking.
A front wheel drives over this lane marking.
Lane markings were detected on both sides of the lane. The front wheel drives over a continuous lane marking.
A brake application may be interrupted at any time if you steer slightly in the opposite direction.
A continuous lane marking was detected and driven over with the front wheel.
A lane marking and an approaching vehicle, an overtaking vehicle or vehicles driving parallel to your vehicle were detected in the adjacent lane. The front wheel drives over the lane marking.
A brake application may be interrupted at any time if you steer slightly in the opposite direction.
You clearly and actively steer, brake or accelerate.
If a driving safety system intervenes, such as ESP®, Active Brake Assist or Active Blind Spot Assist.
You have adopted a sporty driving style with high cornering speeds or high rates of acceleration.
When ESP® is deactivated.
When driving with a trailer, the electrical connection to the trailer has been correctly established.
If a loss of tyre pressure or a defective tyre has been detected and displayed.
If you deactivate the Active Lane Keeping Assist warning and the lane markings cannot be clearly detected, it is possible that no lane correcting brake application takes place More.
If there is poor visibility, e.g. due to insufficient illumination of the road, if there are highly variable shade conditions or in rain, snow, fog or heavy spray.
If there is glare, e.g. from oncoming traffic, the sun or reflections.
If the windscreen in the area of the multifunction camera is dirty, or if the camera is misted up, damaged or covered.
If there are no lane markings, or several unclear lane markings are present for one lane, e.g. around roadworks.
If the lane markings are worn, dark or covered.
If the distance from the vehicle in front is too short and thus the lane markings cannot be detected.
If the lane markings change quickly, e.g. lanes branch off, cross one another or merge.
If the carriageway is very narrow and winding.
Vehicles with Driving Assistance Package: if the radar sensors in the rear bumper are dirty or covered in snow and an obstacle is detected in your lane, no lane-correcting brake application takes place.