Narrow vehicles or vehicles travelling side by side
Narrow vehicles or vehicles travelling side by side are not detected by the radar
sensor until they are within the sensor's range » Fig. 139 - . This is especially
true for narrow vehicles, such as motorcycles.
If necessary, slow down the car by applying the brake.
Other vehicles changing lanes
Vehicles that change onto the lane with a small proximity » Fig. 140 - do not
have to be detected by the radar sensor in time. The result may be a delayed ACC
response.
If necessary, slow down the car by applying the brake.
Stationary vehicles
The ACC does not detect stationary objects! When a vehicle detected by the ACC turns or sheers off and there is a stationary vehicle in front of this vehi-cle, » Fig. 140 -
the ACC does not respond to the stationary vehicle.
In such cases, take over the steering and apply the brake.
When overtaking
When your vehicle is being controlled (the speed is lower than that which is stor-
ed) and the indicator is activated, the ACC interprets that the driver intends to
overtake. The ACC automatically accelerates the vehicle, thereby reducing the
proximity to a vehicle ahead.
If the vehicle changes to the fast lane and no vehicle is detected ahead, the ACC
accelerates until the set speed is reached and then keeps it constant.
Acceleration can be cancelled at any time by touch on the brake pedal or pressing
the button
on the control lever » Fig. 138 on page 151 .
Vehicles with special load or special body parts
Other vehicles with a load or with body parts protruding from the sides, back or
top of the vehicle contour may not be detected by the ACC.
Control should therefore be disabled whenever you are driving behind or overtak-ing such a vehicle.
Towing a trailer
When towing a trailer, the ACC control will be less powerful. The manner of driv- ing should therefore be adapted to this limitation.
Information messages
First read and observe the introductory information and safety warn-
ings
on page 148.
If the symbol
appears in the instrument cluster display when ACC is enabled, it
means that the ACC is not working.
The messages and information are indicated in the instrument cluster display. ACC: no sensor view!
The sensor is dirty or has no “visibility”. Stop the car, switch off the engine and
clean the sensor or remove the obstacle causing the lack of “visibility” » Fig. 135
on page 149 . Should the ACC still be unavailable after the engine is restarted,
push the lever into position
» Fig. 138 on page 151 . Seek help from a specialist
garage.
ACC not available.
Stop the vehicle, switch off the engine and then start it again. If the ACC is still not available, push the lever into position
. Seek help from a specialist garage.
Error: ACC
There is an ACC system error. Push the lever into position .
. Seek help from a
specialist garage.
Speed limit
Increase the speed accordingly and start control » page 152.
Area monitoring system (Front Assist)
Introduction
This chapter contains information on the following subjects:
Instructions and Information
155
Radar sensor
155
Operation
156
Activating/deactivating
157
“City”Emergency braking
157
Information messages
158
154Driving
The area monitoring system (From here on only referred to as Front Assist) warns
you of the danger of a collision with an obstacle in front of the vehicle and tries to
avoid a collision or mitigate its consequences by automatically applying the
brakes as appropriate.WARNING■ Front Assist only works as an aid, it does absolve the driver of the responsi-
bility to maintain full control over the vehicle's steering.■
Front Assist has physical and system related limitations. For this reason, the
driver may experience some undesired or delayed system responses in certain
situations. You should therefore always be alert and ready to intervene!
■
Always adapt your speed and safety proximity to the vehicle ahead to the
current visibility, weather, road and traffic conditions.
■
If Front Assist gives a warning, then, depending on the traffic situation, im-
mediately slow down the car by applying the brakes or avoid the obstacle.
■
The increased safety through the Front Assist system must not tempt you
to take greater risks than otherwise – risk of accident!
■
The driver must always be ready to take over steering of the vehicle himself
(brake or accelerate).
■
Front Assist does not respond to crossing or oncoming objects.
Instructions and Information
First read and observe the introductory information and safety warn-ings
on page 154.
Front Assist may become impaired in the following situations, for example.
› When visibility is poor, (e.g. fog, heavy rain, thick snowfall).
› Driving around “sharp” bends.
› When fully pressing down the accelerator pedal.
› If there is a fault with the Front Assist system.
› When one of the brake assist systems (e.g. ESC) intervenes.
WARNINGIn the following situations, Front Assist should be switched off for safety rea-
sons.■
When the vehicle is being towed away.WARNING (Continued)■ When the vehicle is on a rolling test bench.■When an undesired activation has repeatedly occurred.■
When on a truck, train or a car ferry service or the like.
CAUTION
Narrow vehicles or vehicles travelling side by side are not detected by Front As-
sist via the radar sensor until they are within the sensor's range. This is especially
true for narrow vehicles, such as motorcycles.
Note
In case of failure of more than one brake light on the vehicle or on the electrically
connected trailer, Front Assist not available.
Radar sensor
Fig. 141
Mounting location of the radar
sensor
First read and observe the introductory information and safety warn- ings on page 154.
The radar sensor » Fig. 141 (From here on referred to as sensor) is used to assess
the traffic situation in front of the vehicle.
The sensor can distinguish objects by radiating and receiving electromagneticwaves.
155Assist systems
The sensor function may be impaired in the events of one of the following.
› The sensor is covered by mud, snow or debris, for example.
› The sensor or its immediate surroundings are covered by other objects, for ex-
ample, a sticker is attached.
› When visibility is poor, (e.g. fog, heavy rain, thick snowfall).
If the sensor is dirty or does not have “visibility” for any other reason, the follow-
ing message appears in the instrument cluster display.
Front Assist: no sensor view.
Stop the car, switch off the engine and clean the sensor or eliminate the obstacle
causing the lack of“visibility”. Should Front Assist still be unavailable after the en-
gine is restarted, consult a specialist garage for help.WARNING■ If you suspect that the sensor is damaged, deactivate Front Assist. Have the
sensor checked by a specialist garage.■
The sensor can become misaligned by collisions or by damage to the front of
the vehicle, the wheel arch or the underside of the vehicle. This can lead to
impaired function of the Front Assist function - risk of accidents! If this is the
case, have the sensor checked by a specialist garage.
■
Any improperly carried out work to the front of the vehicle may cause the
sensor to become misaligned. We therefore recommend only having these
modifications and technical alterations carried out by a specialist garage. Please also observed the instructions in » page 200, Service work, adjust-
ments and technical alterations .
■
The area in front of and around the sensor must not be covered with stick-
ers, additional lights or similar items. This can lead to impaired function of the
sensor - risk of accidents!
WARNINGThe sensor may not be able to distinguish all objects correctly under certain
circumstances. You should therefore not use Front Assist in the following ca-
ses - risk of accidents!■
When driving through places where metal objects (such as metal buildings,
railroad tracks, etc.) can be found.
■
When driving through very divided and enclosed spaces (such as large-ca-
pacity garages, car ferries and the like.)
CAUTIONRemove the snow with a brush and the ice with a solvent-free de-icer.
Operation
Fig. 142
Instrument cluster display: Note
(dangerous proximity) / advance
warning or intervention of the
city emergency braking function
First read and observe the introductory information and safety warn-
ings on page 154.
Front Assist assists the driver while driving in the following ways:
› Alerts you about a dangerous proximity to the vehicle ahead.
› Warns you of an impending collision.
› Prepares the brakes for emergency braking prior to a detected danger.
› Assists with a brake action triggered by the driver.
› If the driver fails to respond to a detected danger, an automatic brake action is
performed.
Front Assist can work only if the following basic conditions are met. Front Assist is enabled.
TCS is enabled » page 137, Brake assist systems .
The vehicle is traveling forwards at a speed of more than approx. 5 km/h.
proximity warning (dangerous proximity)
If a safe time interval to the vehicle ahead is exceeded, the display of the instru- ment cluster shows the symbol » Fig. 142 -
.
Immediately increase the proximity if the current traffic situation allows you to do so!
The proximity at which the warning is displayed depends on the current speed.
The warning may occur when driving between about 60 km/h and 210 km/h.
156Driving
Advance warning
If Front Assist detects a risk of collision with a vehicle ahead, a symbol appears in
the display of the instrument cluster and an acoustic signal is heard » Fig. 142 - .
At the same time, the braking system is prepared for possible emergency braking.
The advance warning may occur when driving between 30 km/h and 210 km/h.
Apply the brakes or avoid the obstacle!
Acute alert
If the driver does not react to the advance warning, Front Assist briefly applies
the brake automatically via an active brake intervention to draw attention to the
potential danger of a collision again.
Automatic Braking
If the driver fails to respond to the acute warning, Front Assist starts to apply the
brakes automatically with increasing stopping power in several stages.
Front Assist can help to mitigate the consequences of a potential accident by
means of a speed reduction.
Brake Support
If the driver does not brake sufficiently in case of an imminent collision, Front As-
sist can increase the braking power, thereby reducing the consequences of a po-
tential accident.
The brake support only occurs as long as the brake pedal is being firmly pressed
down.
CAUTION
The automatic braking interventions by Front Assist can be terminated by press-
ing the clutch or the accelerator, or by moving the steering wheel.
Note
If an automatic brake intervention is triggered by Front Assist, the pressure in the
brake system increases and the brake pedal cannot be operated with the normal
pedal stroke.
Activating/deactivating
First read and observe the introductory information and safety warn-ings
on page 154.
Front Assist is automatically activated each time the ignition is switched on.
Front Assist should only be disabled in exceptional cases.
Activate / deactivate front assist
Front Assist can be activated or deactivated in the Infotainment » Infotainment
manual , chapter Vehicle settings (CAR button) or in the MAXI-DOTDis-
play » page 32 , Menu item wizard .
By disabling the system, the proximity warning system and the advance warning are also deactivated.
Activate/deactivate proximity warning
The proximity warning indicator can be activated/deactivated in the Infotain-
ment » Infotainment manual , chapter Vehicle settings (CAR button) .
The set proximity warning remains active even after stopping and starting the ig-
nition.
Activate/deactivate advance warning
The advance warning can be activated/deactivated in the Infotainment » Info-
tainment manual , chapter Vehicle settings (CAR button) .
The set advance warning remains active even after stopping and starting the ig- nition.
“City”Emergency braking
First read and observe the introductory information and safety warn-ings
on page 154.
The “City”Emergency braking function (From here on referred to only as the emer-
gency brake function) is a component of the Front Assist system.
The emergency brake function assists the driver when driving as follows. › Prepares the brakes for emergency braking prior to a detected danger.
› If the driver fails to respond to a detected danger, an automatic brake action oc-
curs with stopping power that increases in several stages.
The emergency brake function intervenes when driving between about 5 km/h
and 34 km / h.
157Assist systems
The emergency brake function is automatically activated or deactivated togetherwith the Front Assist system.
If the emergency brake function triggers an automatic brake action, the display of
the instrument cluster shows the symbol » Fig. 142 on page 156 - .WARNINGThe emergency brake function can slow down the vehicle to a complete
standstill. If the vehicle continues to roll forward after stopping, then it should
be stopped with the footbrake.
CAUTION
Automatic braking interventions by the emergency brake function can be termi-
nated by pressing the clutch or the accelerator, or by moving the steering wheel.
Note
If an automatic brake intervention is triggered by the emergency brake function,
the pressure in the brake system increases and the brake pedal cannot be oper-
ated with the normal pedal stroke.
Information messages
First read and observe the introductory information and safety warn-
ings
on page 154.
The messages and information are indicated in the instrument cluster display.
Front Assist: no sensor view.
The sensor is dirty or has no “visibility”. Stop the car, switch off the engine and clean the sensor or remove the obstacle causing the lack of “visibility” » Fig. 135
on page 149 . If the message appears again after starting the engine, the system
should be disabled » page 157. Seek help from a specialist garage.
Front Assist not available.
Stop the vehicle, switch off the engine and then start it again. If the message ap-
pears again after starting the engine, the system should be disabled » page 157.
Seek help from a specialist garage.
START-STOP
Introduction
This chapter contains information on the following subjects:
Starting/shutting down the engine
159
Operating conditions of the system
160
Manually activating/deactivating the system
160
Information messages
161
The START-STOP system helps you to save fuel while at the same time reducing
harmful exhaust emissions and CO 2 emissions.
The function is automatically activated each time the ignition is switched on.
In the start-stop mode, the engine automatically switches to the vehicle's idle phase, e.g. when stopped at traffic lights. The engine restarts automatically
where necessary.
Information about the current status of the system can be displayed in the Info-
tainment display » operating instructions for Infotainment , chapter Vehicle set-
tings (CAR button) .
The system can work only if the following basic conditions are met. The driver's door is closed.
The driver has fastened the seat belt. The bonnet is closed.
The driving speed was higher than 4 km.h after the last stop.
No trailer is coupled.
WARNING■ The brake servo unit and power steering only operate if the engine is run-
ning.■
Never let the vehicle roll with the engine switched off.
CAUTION
Always deactivate the START-STOPsystem before driving through wa-
ter » page 135 . 158Driving
Note■If the driver's seat belt is removed for more than approx. 30 seconds or the driv-
er's door is opened during stop mode on vehicles with manual transmission or au- tomatic transmission (when the selector lever in position P), the engine must be
started manually » page 121.■
After manually starting the engine on vehicles with manual transmission, auto-
matic engine shut down is not possible until the vehicle has travelled the re-
quired minimum distance for START-STOPP mode.
■
If on vehicles with automatic transmission, the selector lever D/S or N is selec-
ted after moving in reverse, the vehicle will first need to achieve a speed greater
than 10 km/h before automatic engine shut down takes place again.
■
Changes to the outdoor temperature can have an effect on the internal temper-
ature of the vehicle battery even after several hours. If the vehicle remains out-
doors for a long time in minus temperatures or in direct sunlight, it can take sev-
eral hours until the internal temperature of the vehicle battery reaches a suitable
temperature for proper operation of the START STOP system.
■
If the Climatronic is running in automatic mode, it is possible that under certain
conditions the engine may not switch off automatically.
Starting/shutting down the engine
Fig. 143
Instrument cluster display: En-
gine shut down (STOP phase)
First read and observe the introductory information and safety warn- ings on page 158.
Vehicles with manual transmission
›
Stop the vehicle (where necessary, apply the handbrake).
›
Put the gear stick into Neutral.
›
Release the clutch pedal.
Automatic engine shut down (STOP phase) takes place. A check warning icon ap-
pears in the display » Fig. 143 .›
Depress the clutch pedal.
The automatic start procedure takes place again (START phase). The warning icon
goes out.
Vehicles with automatic transmission
›
Bring the vehicle to a stop and depress the brake pedal.
Automatic engine shut down takes place. A check warning icon appears in the display » Fig. 143 .
›
Release the brake pedal.
The automatic start procedure takes place again. The warning icon goes out.
Further information on automatic transmissionEngine shut down takes place when the selector lever is in positions P, D/S , N
and in Tiptronic mode.
When the selector lever is in position P the engine remains shut down after you
release the brake pedal. Start the engine by pressing the gas pedal or by moving
the selector lever into a different mode and releasing the brake pedal.
If the selector lever is moved into position R during the STOP phase , the engine
will re-start.
There is no automatic engine shutdown if the system detects a vehicle move-
ment due to a large steering angle, or when the selector lever is moved to posi-
tion R (e.g. when parking).
No automatic engine shutdown takes place when the vehicle is moving at low speed (e.g. during a traffic jam or when tuning) and remains stationary after
pressing the brake pedal lightly. Automatic engine shutdown takes place if you press the brake pedal down with more force.
159Assist systems
Operating conditions of the systemFig. 144
Instrument cluster display: En-
gine shut down is not currently
available
First read and observe the introductory information and safety warn-
ings on page 158.
The START-STOP system is very complex. Some of the procedures are hard to
check without servicing.
No engine shut down is carried out
Before each STOP phase, the system checks whether certain conditions have
been met. No engine shut down takes place in the following situations.
› The engine has not reached the minimum temperature for START STOP mode.
› The temperature inside the vehicle has not reached the desired temperature
set in the air-conditioning system/heating.
› The external temperature is very low/high.
› The windscreen heater is switched on.
› The intensive windscreen heater (Climatronic) or windscreen heater/ventilation
is switched on with the maximum air temperature setting (manual air condition-
ing system).
› The parking aid/Park Assist is switched on.
› The charge state of the vehicle battery is too low.
› The stationary vehicle is on a steep slope or a steep downhill section.
› The idling speed is too high.
A check warning icon appears in the display
» Fig. 144 .
The automatic start procedure takes place again
During the STOP phase, the engine fires up without any active driver intervention,
e.g. in the following situations.
› The vehicle begins to roll, e.g. on a slope.
› The difference between the temperature setting of the air-conditioning sys-
tem/heating and the temperature of the interior is too large.
› The windscreen heater is switched on.
› The intensive windscreen heater (Climatronic) or windscreen heater/ventilation
is switched on with the maximum air temperature setting (manual air condition-
ing system).
› The brake pedal was pressed several times (the pressure in the braking system
is too low).
› The charge state of the vehicle battery is too low.
› The current consumption is too high.
Manually activating/deactivating the system
Fig. 145
Button for the START-STOP sys-
tem
First read and observe the introductory information and safety warn-
ings on page 158.
Activation/deactivation
›
Press the symbol button
» Fig. 145 .
When start-stop mode is deactivated, the warning light in the button lights up.
Note
■ If the system is deactivated during the STOP phase, the automatic start proce-
dure takes place.■
Selecting the driving mode Eco when the system is deactivated will automati-
cally activate the system » page 161.
160Driving
The engine output falls as the height increases, as does the ability to climb.
Therefore, for every additional 1000 m in height (or part), the maximum permissi- ble towed weight must be reduced by 10%.
The towed weight is made up of the actual weights of the loaded towing vehicleand the loaded trailer.
The trailer and drawbar load information on the type plate of the towing device are merely test data for the towing device. The vehicle-specific values are de-
tailed in the vehicle documents.WARNING■ Do not exceed the maximum permissible axle and drawbar load and the
maximum permissible total or towed weight of the vehicle and the trailer –
risk of accident and serious injury.■
Slipping loads can significantly impair the stability and safety of the vehicle/
trailer combination – risk of accident and serious injury.
Driving with a trailer
Fig. 157
Swivel out the 13-pin power
socket
First read and observe the introductory information and safety warn- ings on page 172.
Before the journey
›
Grip the 13-pin socket at point
A
and swing out in the direction of ar-
row » Fig. 157 .
›
Lift off protective cap
5
» Fig. 152 on page 169 .
After the journey
›
Grip the 13-pin socket at point
A
and swing in the opposite direction to the ar-
row » Fig. 157 .
›Place the protective cover 5
» Fig. 152 on page 169 onto the tow bar.
Safety eye
The purpose of the safety eyelet B
» Fig. 157 is to attach the breakaway cable of
the trailer.
When attaching the breakaway cable to the safety eye, it must sag freely in all
trailer positions (sharp bends, in reverse, etc.).
Exterior mirrors
You have to have additional exterior mirrors fitted if you are not able to see the
traffic behind the trailer with the standard rear-view mirrors. The national legal requirements must be observed.
Headlights
The front of the vehicle may lift up when a trailer is being towed and the head-
lights may dazzle other road users.
Adjust the headlights using the headlight beam control » page 55, Side lights and
low beam .
Driving speed
For safety reasons, do not drive faster than 80 km/h when hitching a trailer.
Immediately reduce your speed as soon as even the slightest swaying of the trail- er is detected. Never attempt to stop the trailer from “swaying” by accelerating.
Brakes
Apply the brakes in good time! If the trailer is fitted with a trailer brake, apply the
brakes gently at first, then brake firmly. This will avoid brake jolts resulting from
the trailer wheels locking.
On downhill sections shift down a gear in good time to also use the engine as a
brake.
Engine overheating
If the needle for the coolant temperature gauge moves into the right-hand area
or the red area of the scale, the speed must be reduced immediately.
Stop and switch off the engine if the warning light
in the display » page 22 is
lit. Wait a few minutes and check the level of coolant » page 222.
The following guidelines must be observed » page 22,
Coolant .
The coolant temperature can be reduced by switching on the heating.
173Towing a trailer