Problem Possible causes/consequences and
M
MSolutions You have lost the emer-
gency key element. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. The engine cannot be
started using the key. The on-board voltage is too low.
X
Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary
(Y page 337).
or
X Jump-start the vehicle (Y page 341).
or
X Consult a qualified specialist workshop. The engine cannot be
started using KEYLESS-
GO. The key is in the
vehicle. A door is open. Therefore, the key cannot be detected as easily.
X
Close the door and try to start the vehicle again. There is interference from a powerful source of radio waves.
X
Start your vehicle with the key in the ignition lock. Doors
Important safety notes
G
WARNING
Only for the United Kingdom: if the vehicle
has been locked with the key, the double lock
function is activated as standard. It is then not
possible to open the doors from inside the
vehicle.
Therefore, do not leave any people behind in
the vehicle, particularly children, elderly peo-
ple or people in need of special assistance if
the vehicle has been locked with the key. As
a result, they may not be able to free them-
selves in the event of an emergency. As a
result, they could be seriously or even fatally
injured by prolonged exposure to extremely
high or low temperatures, for example. In this
case, rescuing people from outside the vehi-
cle is difficult.
Deactivate the interior motion sensor before
you lock the vehicle with the key. The doors can then be opened from the inside after the
vehicle has been locked from the outside with
the key.
G
WARNING
If children are left unsupervised in the vehicle,
they could:
R open a door from inside the vehicle at any
time, even if it has been locked
R start the vehicle using a key which has been
left in the vehicle
R release the parking brake
They could thereby endanger themselves and
others. Never leave children unsupervised in
the vehicle. Always take the key with you
when leaving the vehicle, even if you are only
leaving it for a short time. 82
DoorsOpening and closing
Permanent SPEEDTRONIC
You can use the on-board computer to limit
the speed permanently to a value between
160 km/h(e.g. for driving on winter tyres) and
the maximum speed (Y page 241).
Shortly before the stored speed is reached, it
appears in the multifunction display.
Permanent SPEEDTRONIC remains active,
even if variable SPEEDTRONIC is deactivated.
You cannot exceed the stored limit speed,
even if you depress the accelerator pedal
beyond the pressure point (kickdown). DISTRONIC PLUS
Important safety notes DISTRONIC PLUS regulates the speed and
automatically helps you maintain the dis-
tance to the vehicle detected in front. DIS-
TRONIC PLUS brakes automatically so that
the set speed is not exceeded.
On long and steep downhill gradients, espe-
cially if the vehicle is laden or towing a trailer,
you must select shift range 1,2or 3in good
time. By doing so, you will make use of the
braking effect of the engine. This relieves the
load on the brake system and prevents the
brakes from overheating and wearing too
quickly.
If DISTRONIC PLUS detects a slower-moving
vehicle in front, your vehicle is braked in order
to maintain the preset distance to the vehicle
in front. G
WARNING
Do not change down for additional engine
braking on a slippery road surface. This could
cause the drive wheels to lose their grip and
the vehicle could skid. G
WARNING
DISTRONIC PLUS is only an aid designed to
assist driving. The driver remains fully respon-
sible for the vehicle's distance from other vehicles, the vehicle's speed and for braking
in good time.
DISTRONIC PLUS does not react in particular
to:
R pedestrians
R stationary obstacles on the road, e.g. stop-
ped or parked vehicles
R oncoming and crossing traffic
DISTRONIC PLUS may not detect narrow vehi-
cles driving in front, e.g. motorcycles, or vehi-
cles driving on a different line. Therefore,
always pay attention to traffic conditions even
when DISTRONIC PLUS is activated. Other-
wise, you may fail to recognise dangers in
time, cause an accident and injure yourself
and others. G
WARNING
DISTRONIC PLUS cannot take account of road
and traffic conditions. If DISTRONIC does not
recognise or no longer recognises the vehicle
in front, do not activate DISTRONIC or, if it is
already active, deactivate it. This is especially
the case:
R before corners
R on filter lanes
R when changing to a lane with faster moving
traffic
R in complex driving situations or where lanes
are diverted, e.g. at roadworks on a motor-
way
DISTRONIC PLUS otherwise maintains the
current speed set by you or accelerates up to
the set speed.
DISTRONIC PLUS cannot take account of
weather conditions. Deactivate, or do not
activate, DISTRONIC PLUS:
R if the roads are slippery, snow-covered or
icy. The wheels could lose their grip when
braking or accelerating. The vehicle could
start to skid.
R if the sensors are dirty or there is poor vis-
ibility, e.g. due to snow, rain or fog. Dis-
tance control may be impaired. 178
Driving systemsDriving and parking
Always pay attention to traffic conditions
even when DISTRONIC PLUS is activated.
Otherwise, you may fail to recognise dangers
in time, cause an accident and injure yourself
and others.
The radar sensor system is switched off auto-
matically in the vicinity of radio telescope
facilities (Y page 375).
If you want DISTRONIC PLUS to assist you,
the radar sensor system must be activated
(Y page 242) and operational.
If there is no vehicle in front, DISTRONIC
PLUS operates in the same way as cruise
control in the speed range between
30 km/h and 200 km/h. If a vehicle is driving
in front of you, DISTRONIC operates in the
speed range between 0 km/h and
200 km/h.
Do not use DISTRONIC PLUS on roads with
steep gradients. G
WARNING
DISTRONIC PLUS brakes your vehicle up to a
maximum of 4 m/s 2
depending on its speed.
This corresponds to approximately 40% of
your vehicle's maximum braking power. You
must also apply the brakes yourself if this
braking power is not sufficient.
If DISTRONIC PLUS detects a risk of collision
with a vehicle in front, an intermittent warning
tone sounds. In addition, the ·distance
warning lamp in the instrument cluster lights
up. Brake to avoid a collision.
Cruise control lever With the cruise control lever, you can operate
DISTRONIC PLUS and variable SPEED-
TRONIC.
The LIM indicator lamp on the cruise control
lever indicates which system you have selec-
ted:
R
LIM indicator lamp off: DISTRONIC PLUS
is selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected. :
To store the current speed or a higher
speed
; To set the specified minimum distance
= LIM indicator lamp
? To store the current speed and call up the
last stored speed
A To store the current speed or a lower
speed
B To switch between DISTRONIC PLUS and
variable SPEEDTRONIC
C To deactivate DISTRONIC PLUS
Selecting DISTRONIC PLUS X
Check whether LIM indicator lamp =is off.
If it is off, DISTRONIC PLUS is already selec-
ted.
If it is not, press the cruise control lever in
the direction of arrow B.
LIM indicator lamp =in the cruise control
lever goes out. DISTRONIC PLUS is selec-
ted.
Activating DISTRONIC PLUS, storing
and maintaining the current speed Important safety notes
G
WARNING
The vehicle can be braked when DISTRONIC
PLUS is activated. For this reason, deactivate
DISTRONIC PLUS if the vehicle is to be set in
motion by other means (e.g. in a car wash or
by towing). Driving systems
179Driving and parking Z
or
X
Briefly press the cruise control lever in the
direction of arrow =.
Variable SPEEDTRONIC is selected. LIM
indicator lamp ;in the cruise control lever
lights up.
When you deactivate DISTRONIC PLUS, you
will see the DISTRONIC PLUS off DISTRONIC PLUS off message
in the multifunction display for approximately
five seconds.
i The last speed stored remains stored until
you switch off the engine.
DISTRONIC PLUS is automatically deactiva-
ted if:
R you engage the parking brake.
R you are driving slower than 25 km/h and
there is no vehicle in front, or if the vehicle
in front is no longer detected.
R ESP ®
intervenes or you deactivate ESP ®
.
R the transmission is in the P,Ror Nposition.
R the vehicle is near a radio telescope facility
(Y page 375).
R you switch off the radar sensor system
(Y page 242).
R you pull the cruise control lever towards
you in order to pull away, and the front-
passenger door or one of the rear doors is
open.
R the vehicle has skidded.
If DISTRONIC PLUS is deactivated, you will
hear a warning tone. You will see the DIS‐
DIS‐
TRONIC TRONIC PLUS
PLUSoff
offmessage in the multifunc-
tion display for approximately five seconds.
If the vehicle has been stopped by DISTRONIC
PLUS and a fault occurs in the system, the
Brake Brake immediately
immediately message appears in the
multifunction display. Depress the brake
pedal immediately so that the vehicle does
not roll away. DISTRONIC PLUS is then deac-
tivated, and the message disappears. Tips for driving with DISTRONIC PLUS General notes
The following contains descriptions of certain
road and traffic conditions in which you must
be particularly attentive. In such situations,
brake if necessary. DISTRONIC PLUS is then
deactivated.
Cornering, going into and coming out of a
bend
The ability of DISTRONIC PLUS to detect vehi-
cles when cornering is limited. Your vehicle
may brake unexpectedly or late.
Vehicles which are not driving in the mid-
dle of their lane
DISTRONIC PLUS may not detect vehicles
which are not driving in the middle of their
lane. The distance to the vehicle in front will
be too short. Driving systems
185Driving and parking Z
R
the driver's door is open and the driver's
seat belt is unfastened.
R the engine is switched off, unless it is auto-
matically switched off by the ECO start/
stop function.
R the bonnet is opened.
X Immediately depress the brake pedal firmly
until the warning message in the multifunc-
tion display goes out. This deactivates the
HOLD function.
A horn will also sound at regular intervals if
the HOLD function is activated and you:
R switch the engine off, open the driver's
door and take off your seat belt
R open the bonnet
The sounding of the horn alerts you to the fact
that the vehicle has been parked while the
HOLD function is still activated. If you attempt
to lock the vehicle, the tone becomes louder.
The vehicle is not locked until the HOLD func-
tion is deactivated.
i If the engine has been switched off, it
cannot be started again until the HOLD
function has been deactivated.
If there is a fault in the system or power supply
while the HOLD function is activated, the
message is shown in the multifunction dis-
play. Immediately depress the brake firmly
until the warning message in the multifunc-
tion display goes out.
On vehicles with automatic transmission, you
can also shift into position P. This deactivates
the HOLD function. PARKTRONIC
Important safety notes G
WARNING
PARKTRONIC is only an aid and may not
detect all obstacles. It is not a substitute for
attentive driving.
You are always responsible for safety and
must continue to pay attention to your imme- diate surroundings when parking and
manoeuvring. You could otherwise endanger
yourself and others.
G
WARNING
Make sure that no persons or animals are in
the manoeuvring range. Otherwise, they
could be injured.
PARKTRONIC is an electronic parking aid with
ultrasonic sensors. It indicates visually and
audibly the distance between your vehicle
and an object.
PARKTRONIC is activated automatically if
you:
R switch on the ignition
R shift to position D,Ror Non vehicles with
automatic transmission
R release the parking brake
PARKTRONIC is deactivated at speeds above
18 km/h. It is reactivated at lower speeds.
PARKTRONIC monitors the area around your
vehicle using six sensors in the front and four
sensors in the rear. :
Example: sensors in the front bumper,
left-hand side
Range of the sensors General notes
The sensors must be free of dirt, ice and
slush. Otherwise, they may not function cor-
rectly. Clean the sensors regularly, taking
care not to scratch or damage them
(Y page 321). 188
Driving systemsDriving an
d parking
Side view
Top view
Front sensors
Centre approximately 100 cm
Corners approximately 60 cm
Rear sensors
Centre approximately 120 cm
Corners approximately 80 cm
!
When parking, pay particular attention to
objects above or below the sensors, such as flower pots or trailer drawbars. PARK-
TRONIC does not detect such objects when
they are in the immediate vicinity of the
vehicle. You could damage the vehicle or
the objects.
The sensors may not detect snow and
objects which absorb ultrasonic sources.
Ultrasonic sources, such as an automatic
car wash, a lorry's compressed-air brakes
or a pneumatic drill, could cause PARK-
TRONIC to malfunction.
PARKTRONIC may not function correctly on
uneven terrain.
Minimum distance Centre approximately 20 cm
Corners approximately 15 cm
If there is an obstacle within this range, the
relevant warning displays light up and a warn-
ing tone sounds. If the distance falls below
the minimum, the distance may no longer be
shown.
Warning displays
The warning displays show the distance
between the sensors and the obstacle. The
warning display for the front area is located
on the dashboard above the centre air vents.
The warning display for the rear area is loca-
ted on the roof lining in the rear compart-
ment. Driving systems
189Driving and parking Z
R
you have switched on the turn signals. In
this case, the warnings are suppressed for
a certain period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
Adaptive
If Adaptive
Adaptive is selected, no warning vibration
occurs if:
R you have switched on the turn signals. In
this case, the warnings are suppressed for
a certain period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
R you accelerate hard, e.g. kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid an
obstacle or change lane quickly.
R you cut the corner on a sharp bend.
In order that you are warned only when nec-
essary and in good time if you cross the lane
marking, the system recognises certain con-
ditions and warns you accordingly.
The warning vibration occurs earlier if:
R you approach the outer lane marking on a
bend.
R the road has very wide lanes, e.g. a motor-
way.
R the system recognises solid lane markings.
The warning vibration occurs later if:
R the road has narrow lanes.
R you cut the corner on a bend.
Towing a trailer
If you attach a trailer, make sure that you have
correctly established the electrical connec-
tion. This can be accomplished by checking
the trailer lighting. Active Driving Assistance package
General notes The Active Driving Assistance package con-
sists of DISTRONIC PLUS (Y
page 178), Active
Blind Spot Assist (Y page 203) and Active
Lane Keeping Assist (Y page 210).
Active Blind Spot Assist Important safety notes
G
WARNING
Active Blind Spot Assist is only an aid and may
detect vehicles/obstacles incorrectly or not
at all.
The system may be impaired or may not func-
tion if:
R there is poor visibility, e.g. due to snow,
rain, fog or spray.
R the rear and/or front sensors are dirty.
Active Blind Spot Assist may not detect nar-
row vehicles, such as motorcycles or bicycles,
or only detect them too late. It cannot detect
vehicles which are overtaken at a small dis-
tance and then enter the blind spot area.
Active Blind Spot Assist cannot detect road
and traffic conditions. It is not a substitute for
attentive driving. You are responsible for the
vehicle's speed, braking in good time, and
steering correctly. Always adapt your driving
style to suit the prevailing road and weather
conditions. Always pay attention to traffic
conditions and your surroundings. Otherwise,
you may fail to recognise dangers in time,
cause an accident and injure yourself and oth-
ers.
Active Blind Spot Assist uses a radar sensor
system to monitor the area to the sides of
your vehicle which are behind the driver. A
warning display in the exterior mirrors draws
your attention to vehicles detected in the
monitored area. If you then switch on the cor-
responding turn signal to change lane, you
will also receive an optical and audible colli-
sion warning. If a risk of lateral collision is Driving syste
ms
207Driving an d parking Z
detected, corrective braking may help you
avoid a collision. To support the course-cor-
recting brake application, Active Blind Spot
Assist also uses the forward-facing radar sen-
sor system. Active Blind Spot Assist supports
you from a speed of approximately 30 km/ h.
The radar sensor system is switched off auto-
matically in the vicinity of radio telescope
facilities (Y page 375).
For Active Blind Spot Assist to assist you
when driving, the radar sensor system must
be activated (Y page 242) and operational.
Monitoring range of the sensors G
WARNING
Active Blind Spot Assist monitors certain
areas in the immediate vicinity of your vehicle.
Vehicles that approach and drive past at high
speeds are not detected. No visual nor audi-
ble warnings are emitted and the system does
not brake the vehicle to correct your course.
If the lanes are very wide, it may not be pos-
sible to monitor the complete width of the
neighbouring lane. For this reason, vehicles in
the next lane may not be detected, especially
if they are driving in a staggered formation.
This may be the case if vehicles are driving at
the edge of their lane that is furthest away
from your vehicle.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognise dangers in time, cause an accident
and injure yourself and others.
Active Blind Spot Assist monitors the area up
to three metres behind your vehicle and
directly next to your vehicle as shown in the
diagram. For this purpose, Active Blind Spot
Assist uses radar sensors in the rear bumper. Example: Saloon
If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may
be indicated, especially if the vehicles are not
driving in the middle of their lane. This may
be the case if there are vehicles at the edge
of their lane nearest your vehicle.
Due to the nature of the system:
R warnings may be issued in error when driv-
ing close to crash barriers or similar solid
lane borders.
R warnings may be interrupted when driving
alongside long vehicles, for example lor-
ries, for a prolonged time.
Two Active Blind Spot Assist radar sensors
are integrated into the front and rear bumpers
respectively. An additional radar sensor is
located behind the cover in the radiator grille.
Make sure that the sensors and the areas
around them are free of dirt, ice or slush. The
rear sensors must not be covered, e.g. by
bicycle racks or overhanging loads. Following
a severe impact or in the event of damage to
the bumpers, have the function of the sensors
checked at a qualified specialist workshop.
Blind Spot Assist may otherwise not work
properly. 208
Driving systemsDriving and parking