
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 %/& 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 350).
or
X Jump-start the vehicle (Y page 354).
or
X Consult a qualified specialist workshop. The engine cannot be
started using the key.
The steering lock is mechanically blocked
6
.
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, 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:
6 Not on vehicles with the DIRECT SELECT lever. 88
DoorsOpening and closing

The auxiliary heating switches off automati-
cally after 50 minutes. This time limit can be
altered. Please contact a qualified specialist
workshop for this purpose.
You cannot use the auxiliary ventilation to
cool the vehicle interior to a temperature
lower than the outside temperature.
Before switching on X
Turn the key to position 2in the ignition
lock.
X Set the temperature.
The auxiliary heating/ventilation can be acti-
vated even when the climate control is being
controlled manually. Optimum comfort can
be attained when the system is set to auto-
matic mode. Set the temperature to 22 †.
The auxiliary heating/ventilation can 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 departure times, one of which
may be preselected (Y page 247).
Switching the auxiliar yheating/venti-
lation on/off using the centre console
button Button on the centre console 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 247)
Switching on auxiliary heating/ventila-
tion
X Press button :.
The red or blue indicator lamp in but-
ton :lights up.
Switching off auxiliary heating/ventila-
tion
X 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 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 148). 146
Operating the climate control systemClimate control

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 comple xdriving 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. 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 rada rsensor system is automatically
deactivated near radio telescope facilities
(Y page 398).
If you want DISTRONIC PLUS to assist you,
the radar sensor system must be activated
(Y page 247) 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/ha nd 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. G
WARNING
DISTRONIC PLUS brakes 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.
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. 186
Driving systemsDriving and parking

Example: vehicles featuring automatic transmis-
sion with a DIRECT SELECT lever
: Vehicle in front, if detected
; Distance indicator: current distance to
the vehicle in front
= Specified minimu mdistance to the vehi-
cle in front; adjustable
? Own vehicle
Displa ywhen DISTRONIC PLUS is activa-
ted
You will see the stored speed for about five
seconds whe nyou activate DISTRONIC PLUS.
After this time, you will see the following in
the multifunction display while DISTRONIC
PLUS is activated: Example: vehicles featuring automatic 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 Deactivating DISTRONIC PLUS
There are several ways to deactivate DIS-
TRONIC PLUS:
X
Briefly press the cruise control lever for-
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, the
DISTRONIC PLUS off message is shown 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 if you deactivate ESP ®
.
R the transmission is in the P,Ror Nposition.
R the vehicle is near a radio telescope facility
(Y page 398).
R you switch off the radar sensor system
(Y page 247). 192
Driving systemsDriving and parking

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 20 seconds. The PARKTRONIC sensors are dirty or there is interference.
X
Cleant he PARKTRONIC sensors (Y page 330).
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 Parking Guidance is an electronic parking aid
with ultrasound. Ultrasound is used to meas-
ure the road on both sides of the vehicle. A
suitable parking space is indicated by the
parking symbol. You receive steering instruc-
tions when parking. You may also use PARK-
TRONIC (Y page 200). 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 Driving systems
203Driving 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 133). The windscreen is smeared after the vehicle has been cleaned in
a car wash.
X
Cleant he windscreen (Y page 329). 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 143). The windscreen is iced up.
X
De-ice the windscreen (Y page 142). There is dirt on the inside of the windscreen.
X
Cleant he inside of the windscreen (Y page 329).Lane Tracking package
General notes The Lane Tracking package consists of Blind
Spot Assist (Y
page 212) and Lane Keeping
Assist (Y page 214).
Blind Spot Assist Important safety 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. 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.
The radar sensor system is automatically
deactivated near radio telescope facilities
(Y page 398).
For Blind Spot Assist to assist you when driv-
ing, the radar sensor system must be activa-
ted (Y page 247) and operational. 212
Driving systemsDriving and parking

Blind Spot Assist (Y
page 216) and Active
Lane Keeping Assist (Y page 218).
Active Blind Spot Assist Important safety notes
Active Blind Spot Assist uses a radar sensor
system to monitor the side areas of your vehi-
cle which are behind the driver.
Awarning
display in the exterior mirrors draws your
attentio nto vehicles detected in the moni-
tored area. If you then switch on the corre-
sponding turn signal to change lane, you will
also receive an optical and audible collision
warning. If a risk of lateral collision is detec-
ted, corrective braking may help you avoid a
collision. To support the course-correcting
brake application, Active Blind Spot Assist
also uses the forward-facing radar sensor sys-
tem. Active Blind Spot Assist supports you
from a speed of approximately 30 km/h. 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. The radar sensor system is automatically
deactivated near radio telescope facilities
(Y
page 398).
For Active Blind Spot Assist to assist you
when driving, the radar sensor system must
be activated (Y page 247) and operational.
Monitoring range
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
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. 216
Driving systemsDriving and parking