⇒ Operating the speed limiter with the multifunction steering wheel
⇒ Troubleshooting
The speed limiter helps you to stop exceeding a stored speed.
Speed range
The speed limiter is available when driving forwards at speeds from approx. 30 km/h (20 mph).
Driving with the speed limiter
You can interrupt the speed limiter at any time by depressing the accelerator all the way down past
the point of resistance. As soon as the stored speed is exceeded, the green indicator lamp will
flash and an acoustic warning may sound. The speed remains stored in the memory.
The speed limiter function switches back on automatically as soon as the speed drops back below
the stored speed.
Displays
When the speed limiter is switched on, the instrument cluster display shows the stored speed and
the status of the speed limiter:
Shown small or grey: speed limiter not active.Shown large or white: speed limiter active.
Driving downhill
Driving downhill may cause the set speed to be exceeded.
Apply the foot brake to slow the vehicle down, and change down a gear as required.
WARNING
Always switch off the speed limiter after use to avoid unintentional speed control.
The speed limiter does not relieve the driver of their responsibility for the speed of the vehicle. Do
not drive at full throttle if this is not required.
Use of the speed limiter in adverse weather conditions is dangerous and can cause serious injury,
e.g. through aquaplaning, snow, ice, or leaves. Use the speed limiter only when the road and
weather conditions allow it to be used safely.
The speed limiter cannot limit the vehicle speed when travelling downhill. The vehicle speed can
increase under its own weight. Select a lower gear or use the foot brake to slow the vehicle down.
Operating the speed limiter with the multifunction steering wheel
If automatic deceleration by ACC is not sufficient, ACC will request you to brake additionally by a
corresponding message on the instrument cluster. In addition, the red warning lamp lights up
and an acoustic warning is given. Brake immediately!
Radar sensor
ACC detects driving situations by means of the radar sensor at the front of the vehicle ⇒ Front view .
The radar sensor has a range of up to approximately 120 m.
WARNING
The intelligent technology used in the ACC cannot overcome the laws of physics, and functions only
within the limits of the system. Never let the extra convenience tempt you into taking safety risks
when driving. Careless or unintentional use of the Adaptive Cruise Control (ACC) can cause accidents
and lead to serious injury. The system is not a substitute for the full concentration of the driver.
Adapt your speed and distance from the vehicles ahead to suit visibility, weather, road and traffic
conditions.
Never use the ACC in poor visibility, on steep or winding roads, or on slippery road surfaces e.g. due
to snow, ice, wet roads, loose chippings, or on flooded roads.
Never use the ACC offroad or on non-surfaced roads. The ACC is designed for use on surfaced roads
only.
The ACC will not react to stationary vehicles.
The ACC will not react to persons, animals or vehicles crossing or approaching in the same lane.
Brake immediately if speed reduction by ACC is not sufficient.
Brake immediately if a request to brake appears on the instrument cluster display.
Brake if the vehicle starts rolling unintentionally after a request to brake.
Be prepared to control the speed yourself at all times.
Special driving situations
Fig. 118 On the instrument cluster display: slower vehicle detected in the left-hand lane (illustration).
Fig. 119 Driving through bends. Vehicles outside the range of the radar sensor.
Fig. 120 Vehicle changes lane. Turning vehicle and stationary vehicle.
First read and observe the introductoryinformation and safety warnings⇒Introduction
When not to use ACC
Driving in heavy rain, snow or heavy spray.
Driving through tunnels.
Driving through road works.
Driving on twisting roads, e.g. mountain roads.
Driving offroad.
Driving in multi-storey car parks.
Driving on roads with embedded metal objects, e.g. railway tracks.
Driving on roads with loose chippings.
Vehicles without inside overtaking prevention function: driving on multi-lane roads when
vehicles in the overtaking lane are driving more slowly.
Delayed response
Fig. 122 On the instrument cluster display: setting the distance (illustration, ACC regulating).
First read and observe the introductoryinformation and safety warnings⇒Introduction
Setting the distance
You can set the distance in five steps from very small to very large:
Press the button and then the or button.
Alternatively, press the button as often as necessary until the desired distance is set.
The instrument cluster display shows the chosen distance setting ⇒ Fig. 122① . Please observe any
country-specific requirements for the minimum distance.
You can set the distance which should be set at the start of control operation in the vehicle settings
of the Infotainment system ⇒ Vehicle settings menu .
If ACC is not regulating, the set distance and vehicle are not highlighted on the instrument cluster
display.
Setting the speed
You can adjust the stored speed within the defined speed range by means of the buttons on the
multifunction steering wheel:
+ 1 km/h (1 mph)- 1 km/h (1 mph)+ 10 km/h (5 mph)- 10 km/h (5 mph)
Press and hold the corresponding button to continuously change the stored speed.
Setting the control behaviour
Vehicles with driving profile selection: set the desired driving profile ⇒ Driving profile selection
and 4MOTION Active Control .
Vehicles without driving profile selection: set the desired gearbox programme in the vehicle
settings of the Infotainment system ⇒ Vehicle settings menu .
The brake pedal will feel harder during an automatic braking operation.
Radar sensor
Front Assist detects driving situations by means of the radar sensor at the front of the vehicle
⇒ Front view . The radar sensor has a range of up to approximately 120 m.
Functions included in the system
The City Emergency Braking System and Pedestrian Monitoring (depending on vehicle equipment)
are part of Front Assist and are automatically active when Front Assist is switched on.
WARNING
The intelligent technology used in Front Assist cannot overcome the laws of physics, and functions
only within the limits of the system. Never let the extra convenience afforded by Front Assist tempt
you into taking safety risks when driving. The driver is always responsible for braking in time.
If Front Assist issues a warning, brake your vehicle immediately depending on the traffic situation or
avoid the obstacle.
Adapt your speed and distance from the vehicles ahead to suit visibility, weather, road and traffic
conditions.
Front Assist cannot prevent accidents and serious injuries on its own.
Front Assist can issue unnecessary warnings and carry out unwanted braking interventions in certain
complex driving situations, e.g. at traffic islands.
Front Assist can issue unnecessary warnings and carry out unwanted braking interventions when its
function is impaired, e.g. if the radar sensor is dirty or its position has been changed.
Front Assist without Pedestrian Monitoring does not react to persons. In addition, the system does
not react to animals or to vehicles that are crossing or approaching in the same lane.
If you are unsure whether your vehicle possesses Pedestrian Monitoring, please enquire about this
at a qualified workshop before starting your journey.
Be prepared to take over control of the vehicle yourself at all times.
Warning levels and braking intervention
First read and observe the introductoryinformation and safety warnings⇒Introduction
Distance warning
The system detects when safety is endangered by driving too close to the vehicle in front. The
warning lamp lights up. Increase the distance.
Speed range: around 65 km/h (40 mph) to 250 km/h (155 mph).
Advance warning
The system is able to detect possible collisions with vehicles in front or pedestrians crossing in front
of the vehicle and prepares the vehicle for a possible emergency braking procedure.
A warning tone sounds and the red warning lamp lights up. Brake or take avoiding action.
Speed range: around 30 km/h (20 mph) to 250 km/h (155 mph).
Urgent warning
If the driver does not react to the advance warning, the system may initiate a short braking jolt in
order to draw attention to the increasing collision risk. Brake or take avoiding action.
Speed range: around 30 km/h (20 mph) to 250 km/h (155 mph).
Automatic braking
If the driver also does not react to the urgent warning, the vehicle can be braked automatically with
braking force that increases in several stages. The reduced speed means that it is possible to
minimise the consequences of an accident.
Speed range: around 5 km/h (3 mph) to 250 km/h (155 mph).
Braking intervention
If the system detects that the driver is braking insufficiently when there is a risk of collision, the
system can increase the braking force and help prevent a collision. The braking intervention takes
place only for as long as the brake pedal is pressed hard.
Speed range: around 5 km/h (3 mph) to 250 km/h (155 mph).
City Emergency Braking System
The City Emergency Braking System is part of Front Assist. If the driver does not react to a possible
collision, the system can also automatically brake the vehicle with increasing braking force without
any advance warning.
The red warning lamp lights up
Speed range: around 5 km/h (3 mph) to 30 km/h (20 mph).
Limits of Front Assist
First read and observe the introductoryinformation and safety warnings⇒Introduction
Front Assist is not available or its functions are restricted for a period of around 30 seconds (also
longer, depending on the driving situation) immediately after the vehicle is started.
Front Assist has physical and system-related limitations. You should therefore always be prepared to
take full control of the vehicle if necessary.
Delayed response
If the radar sensor is exposed to environmental conditions that impair sensor functioning, the
system may detect this only after a certain time. For this reason, possible functional restrictions may
be displayed only after a delay at the start of the journey and when driving ⇒ .
WARNING
Failure to switch off Front Assist in the situations mentioned can result in accidents and serious
injuries.
Pedestrian Monitoring
First read and observe the introductoryinformation and safety warnings⇒Introduction
Pedestrian Monitoring can help to avoid accidents with pedestrians crossing the vehicle's path or to
mitigate the consequences of an accident.
The system gives a warning when there is a risk of collision, prepares the vehicle for emergency
braking, helps to brake the vehicle or performs an automatic brake intervention. In the event of an
advance warning, the warning lamp lights up in the instrument cluster
When Front Assist is switched on, Pedestrian Monitoring is active as part of Front Assist in a vehicle
speed range from approx. 5 km/h (3 mph) to 65 km/h (40 mph).
Pedestrian Monitoring is not available in all countries, depending on the vehicle equipment level.
WARNING
The intelligent Pedestrian Monitoring technology cannot overcome the laws of physics, and
functions only within the limits of the system. Never let the extra convenience afforded by the
Pedestrian Monitoring system tempt you into taking any safety risks when driving. The driver is
always responsible for braking in time.
If Pedestrian Monitoring issues a warning, brake your vehicle immediately depending on the traffic
situation or avoid the pedestrian.
Pedestrian Monitoring cannot prevent accidents and serious injuries on its own.
Pedestrian Monitoring can issue unnecessary warnings and carry out unwanted braking
interventions in complex driving situations, e.g. on a main road that turns sharply.
Pedestrian Monitoring can issue unnecessary warnings and carry out unwanted braking
interventions when its function is impaired, e.g. if the radar sensor is covered or its position has
been changed.
Be prepared to take over control of the vehicle yourself at all times.
Operating the area monitoring system (Front Assist)
First read and observe the introductoryinformation and safety warnings⇒Introduction
Front Assist and the advance warning (in some countries) are automatically switched on when you
switch on the ignition.
However, the system is not available or its functions are restricted for a period of around 30 seconds
(also longer, depending on the driving situation).
If the problem persists, switch off Front Assist and go to a qualified workshop.
Lane keeping system (Lane Assist)
Introduction
This chapter contains information on the followingsubjects:
⇒ Driving with the lane keeping system
⇒ Troubleshooting
The lane keeping system (Lane Assist) helps the driver stay in lane.
Using a camera in the windscreen, the lane departure warning system detects lane markings on the
road. If your vehicle moves too close to a recognised lane marking, the system will warn the driver
with a corrective steering intervention. The corrective steering intervention can be overridden by
the driver at any time.
Adaptive lane guidance (depending on vehicle equipment)
The adaptive lane guidance system detects the preferred position in a lane and keeps the vehicle in
this position.
Adaptive lane guidance is switched on and off in the Driver assistance menu in the Infotainment
system ⇒ Vehicle settings menu .
System limits
Use the lane keeping system only on motorways and good main roads.
The system is not active under the following conditions:
The lane keeping system has not detected any lane markings.
WARNING
The intelligent technology used in the lane keeping system cannot overcome the laws of physics, and
functions only within the limits of the system. Always take care when using the lane departure
warning system otherwise you could cause accidents or injuries. The system is not a substitute for
the full concentration of the driver.
Adapt your speed and distance from the vehicles ahead to suit visibility, weather, road and traffic
conditions.
Your hands should always be on the steering wheel so that you can steer at any time. The driver is
always responsible for staying in lane.
The lane keeping system cannot recognise all lane markings. Poor road surfaces, road structures or
objects could be recognised incorrectly as lane markings by the lane keeping system. The lane
keeping system should be switched off immediately in these situations.
Follow the information on the instrument cluster display and respond according to the commands.