
Problems with the key
Problem Possible causes/consequences and
M Solutions
You cannot lock or
unlock the vehicle
using the key. The key battery is discharged or nearly discharged.
X
Try again to lock/unlock the vehicle using the remote control
function of the key. Point the tip of the key at the driver's door
handle from close range and press the %or& button.
If this does not work:
X Check the key battery (Y page 85) and replace it if necessary
(Y page 85).
X Lock (Y page 90) or unlock (Y page 90) the vehicle using
the emergency key element. The key is faulty.
X
Lock (Y page 90) or unlock (Y page 90) the vehicle using
the emergency key element.
X Have the key checked at a qualified specialist workshop. You can no longer lock
or unlock the vehicle
using KEYLESS-GO. KEYLESS-GO is in standby mode because the vehicle has not been
unlocked for an extended period.
X
Pull the door handle and then turn the key to position 2in the
ignition lock. There is interference from a powerful source of radio waves.
X Lock/unlock the vehicle using the remote control function of
the key. Point the tip of the key at the driver's door handle from
close range and press the %/& button. There is a fault with KEYLESS-GO.
X
Lock/unlock the vehicle using the remote control function of
the key. Point the tip of the key at the driver's door handle from
close range and press the %/& button.
X Have KEYLESS-GO checked at a qualified specialist workshop.
If this does not work:
X Check the key battery (Y page 85) and replace it if necessary
(Y page 85).
X Lock (Y page 90) or unlock (Y page 90) the vehicle using
the emergency key element. You have lost a key. X
Have the key deactivated at a qualified specialist workshop.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. Key
87Opening and closing Z

Problem Possible causes/consequences and
M Solutions
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 369).
or
X Jump-start the vehicle (Y page 370).
or
X Consult a qualified specialist workshop. Only vehicles without a
DIRECT SELECT lever:
The engine cannot be
started using the key. The steering lock is mechanically blocked.
X
Remove the key and reinsert it into the ignition lock. While doing
this, turn the steering wheel in both directions. The engine cannot be
started using KEYLESS-
GO. The key is in the
vehicle. Ad
oor 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 or with KEY-
LESS-GO, the double lock function is activa-
ted 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 requiring special assistance. As
a result, they may not be able to free them-
selves in the event of an emergency. They
could be seriously or even fatally injured by
prolonged exposure to extremely high or low
temperatures, for example. In this case, res- cuing people from outside the vehicle is diffi-
cult.
Deactivate the interior motion sensor before
you lock the vehicle. The doors can then be
opened from the inside after the vehicle has
been locked from the outside.
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 akey which has been
left in the vehicle
R release the parking brake 88
DoorsOpening and closing

when the system is set to automatic mode.
Set the temperature to 22 †.
The auxiliary heating/ventilatio ncan be acti-
vated or deactivated using the remote control
or the button on the centre console.
The on-board computer can be used to spec-
ify up to three departur etimes, one of which
may be preselected (Y page 262).
Switching the auxiliar yheating/venti-
lation on/off using the centre console
button The colours of the indicator lamps on the but-
to nh ave the following meanings:
Blue Auxiliary ventilatio nswitched on
Red Auxiliary heating switched on
Yellow Departure time preselected (Ypage 262) Switch in the centre console
X
To switch the auxiliary heating/ventila-
tion on: press button :.
The red or blue indicator lamp in but-
ton :lights up.
X To switch the auxiliary heating/ventila-
tion off: press button :.
The red or blue indicator lamp in but-
ton :goes out. Switching the auxiliary heating/venti-
lation on/off using the remote control Points to observe before use
Your vehicle comes with one remote control.
You may use two additional remote controls
for your vehicle. For more information, please
contac
taqualified specialist workshop.
The remote control has a maximum range of
approximately 300 metres. This range is
reduced by:
R sources of radio interference
R solid objects between the remote control
and the vehicle
R the remote control being in an unfavoura-
ble position in relation to the vehicle
R transmitting from an enclosed space
i The optimum range can be achieved if you
hold the remote control vertically, pointing
upwards when you press one of the but-
tons.
i Abattery symbol appears in the display
when the battery in the remote control is
low. Replace the remote control battery
(Y page 154).
Switching the auxiliary heating/ventila-
tion on/off Auxiliary heating remote control
: Display
; . To check the status/set the depar-
ture time
= ^ To switch off the auxiliary heating/
ventilation 152
Operating the climate control systemClimate control

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.
Always pay attention to traffic conditions
even when DISTRONIC PLUS is activated.
Otherwise, you may fail to recognise dangers
in time, cause an acciden tand injure yourself
and others. G
WARNING
DISTRONIC PLU Sbrakes yourv ehicle 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 avehicle in front, an intermittent warning
tone sounds. In addition, the ·distance
warning lamp in the instrument cluster lights
up. Brake to avoid a collision.
General 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 effec tofthe 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.
If you want DISTRONIC PLUS to assist you,
the radar sensor system must be activated
(Y page 262) and operational. The radar sensor system is switched off auto-
matically in the vicinity of radio telescope
facilities (Y
page 451).
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 avehicle is driving
in front of you, DISTRONIC operates in the
speed range between 0km/h and
200 km/h.
Do not use DISTRONIC PLUS on roads with
steep gradients.
Cruise control lever :
To store the current spee dorahigher
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
With the cruise control lever, you can operate
DISTRONIC PLUS and variable SPEED-
TRONIC. 196
Driving systemsDriving and parking

Display when DISTRONIC PLUS is activa-
ted Example: vehicles featurin
gautomatic transmis-
sion with a DIRECT SELECT lever
: DISTRONIC PLUS activated
; Own vehicle
= Specified minimum distance to the vehi-
cle in front; adjustable
? Vehicle in front, if detected
X Select the Distance display function
using the on-board computer
(Y page 256).
i You will see the stored speed for about
five seconds when you activate DISTRONIC
PLUS.
Deactivating DISTRONIC PLUS There are several ways to deactivate DIS-
TRONIC PLUS:
X Briefly press the cruise control leve rfor-
wards :.
or X
Brake, unless the vehicle is stationary.
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 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 451).
R you switch off the radar sensor system
(Y page 262).
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‐ TRONIC PLUS off message in the multifunc-
tion display for approximately five seconds.
Vehicles with automatic transmission with
selector lever: if the vehicle has been stopped
by DISTRONIC PLUS and a fault occurs in the
system, the Brake immediately message
appears in the multifunction display .Depress
the brake pedal immediately so that the vehi-
cle does not roll away. DISTRONIC PLUS is
then deactivated, and the message disap-
pears. Driving systems
203Driving and parking Z

Problems with PARKTRONIC
Problem Possible causes/consequences and
M Solutions
Only the red segments
in the PARKTRONIC
warning displays are lit.
You also hear a warning
tone for approximately
two seconds.
PARKTRONIC is deacti-
vated after approx-
imately 20 seconds,
and the indicator lamp
in the PARKTRONIC
button lights up. PARKTRONIC has malfunctioned and has switched off.
X
If problems persist, have PARKTRONIC checked at a qualified
specialist workshop. Only the red segments
in the PARKTRONIC
warning displays are lit.
PARKTRONIC is deacti-
vated after approx-
imately 20seconds. The PARKTRONIC sensors are dirty or there is interference.
X
Cleant he PARKTRONIC sensors (Y page 354).
X Switch the ignition back on. The problem may be caused by an external source of radio or
ultrasound waves.
X See if PARKTRONIC functions in a different location. Parking Guidance
Important safety notes G
WARNING
Parking Guidance is merely an aid and may
recommend parking spaces that are not suit-
able for parking. For example, these might be
spaces where parking is prohibited, drive-
ways, unsuitable surfaces, etc.
Parking Guidance measures the parking
space as you drive past it. Any later changes
to the parking space are not taken into
account. For instance, this may be the case
when the vehicle parked in front of or behind
the space changes its position or when an
obstacle is moved into the parking space.
Parking Guidance does not relieve you of the
responsibility for paying attention. If you rely
solely on Parking Guidance, you could cause
an accident and injure yourself and others. You are always responsible for safety and
must continue to pay attention to your imme-
diate surroundings when parking and
manoeuvring.
G
WARNING
Objects located above the height range of
Parking Guidance will not be detected when
the parking space is measured. These are not
taken into account when the parking proce-
dure is calculated, e.g. overhanging loads, tail
sections or loading ramps of goods vehicles.
In some circumstances, Parking Guidance
might therefore issue steering instructions
too soon. This may lead to a collision. For this
reason, you should avoid using Parking Guid-
ance in such situations. Driving systems
215Driving and parking Z

Problems with Night View Assist Plus
Problem Possible causes/consequences and
M Solutions
The picture quality of
Night View Assist Plus
has deteriorated. The windscreen wipers are smearing the windscreen.
X
Replace the wiper blades (Y page 139). The windscreen is smeared after the vehicle has been cleaned in
a car wash.
X
Cleant he windscreen (Y page 353). There is windscreen chip damage in the camera's field of vision.
X
Replace the windscreen. The windscreen is misted up on the inside.
X Demist the windscreen (Y page 149). The windscreen is iced up.
X
De-ice the windscreen (Y page 148). There is dirt on the inside of the windscreen.
X
Cleant he inside of the windscreen (Y page 353).Lane Tracking package
General notes The Lane Tracking package consists of Blind
Spot Assist (Y page 225) and Lane Keeping
Assist (Y page 227).
Blind Spot Assist Important safety notes
G
WARNING
Blind Spot Assist is only an aid designed to
assist driving. It may fail to detect some vehi-
cles and is no substitute for attentive driving.
Blind Spot Assist cannot detect road and traf-
fic conditions. It may fail to detect narrow
vehicles, such as motorcycles or bicycles, or
only detect them too late.
Monitoring may be affected by dirty sensors,
strong spray or poor visibility caused by snow,
rain or mist, for example. In this case, vehicles
are detected late or not at all. 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.
General notes
Blind Spot Assist uses a radar sensor system
to monitor the areas on both sides of your
vehicle. It supports you from speeds of
30 km/h. A warning display in the exterior
mirrors draws your attention to vehicles
detected in the monitored area. If you then
switch on the corresponding turn signal to
change lane, you will also receive an optical
and audible collision warning. For monitoring,
Active Blind Spot Assist uses sensors in the
rear bumper.
For Blind Spot Assist to assist you when driv-
ing, the radar sensor system must be activa-
ted (Y page 262) and operational.
The radar sensor system is automatically
deactivated near radio telescope facilities
(Y page 451). Driving systems
225Driving and parking Z

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. Active Driving Assistance package
General notes The Active Driving Assistance package con-
sists of DISTRONIC PLUS (Y page195), Active
Blind Spot Assist (Y page 229) and Active
Lane Keeping Assist (Y page 232).
Active Blin dSpot 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 poo rvisibility, 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 the mtoo 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.
General notes
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 warn-
ing. If a risk of lateral collision is detected,
corrective braking may help you avoid a col-
lision. To support the course-correcting brake
application, Active Blind Spot Assist uses the
forward-facing radar sensor system. The free
space in the direction of travel is then evalu-
ated.
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 451).
For Active Blind Spot Assist to assist you
when driving, the radar sensor system must
be activated (Y page 262) and operational.
Monitoring range 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 Driving systems
229Driving and parking
Z