
X
Press emergency key element ;into the
opening in the key in the direction of the
arrow until battery compartment cover :
opens. When doing so, do not hold battery
compartment cover :shut.
X Remove battery compartment cover :.=
Battery
X Repeatedly tap the key against your palm
until battery =falls out.
X Inser tthe new battery with the positive ter-
minal facing upwards. Use a lint-free cloth
to do so.
X Make sure that the surface of the battery is
free from lint, grease and all other forms of
contamination.
X Insert the front tabs of battery compart-
ment cover :into the housing and then
press to close it.
X Insert emergency key element ;into the
key (Y page 84).
X Check the function of all key buttons on the
vehicle. 86
KeyOpening and closing 

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.
:
Example: sensors in the front bumper,
left-hand side
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 354). Example: side view Example: top view
Front sensors
Centre Approx. 100 cm
Corners Approx. 60 cm
Rear sensors
Centre Approx. 120 cm
Corners Approx. 80 cm
Minimum distance
Centre Approx. 20 cm
Corners Approx. 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 distanc
emay no longer be
shown. 212
Driving systemsDriving and parking 

steering correctly. Always adapty
our 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 Lane Keeping Assist monitors the area in
front of your vehicle by means of a cam-
era
:at the top of the windscreen. Lane
Keeping Assist detects lane markings on the
road and warns you before you leave your
lane unintentionally.
If you have selected km as the display unit in
the Display unit Speed-/odome‐ ter (Y
page 258) function in the on-board
computer, Lane Keeping Assist assists you at
speeds above 60 km/h. If miles is selected
as the display unit, the assistance range
starts at 40 mph.
A warning may be given if a front wheel
passes over a lane marking. It will warn you
by means of intermittent vibration in the
steering wheel for up to 1.5 seconds. Activating Lane Keeping Assist Example: vehicles featuring automatic transmis-
sion with a DIRECT SELECT lever
X
Switch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard or
Adaptive (Y
page 257).
Symbol :appears in the multifunction
display.
If you are driving faster than 60 km/h and
lane markings are detected, symbol :is
highlighted. Lane Keeping Assist is ready
for use.
Standard
If Standard 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 ®
.
Adaptive
If 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 228
Driving systemsDriving and parking 

No lane-correcting brake application occurs
if:
R
you clearly and actively steer, brake, or
accelerate.
R you cut the corner on a sharp bend.
R you have switched on the turn signals.
R a driving safety system intervenes, such as
ESP ®
, PRE-SAFE ®
Brake or Active Blind
Spot Assist.
R you have adopted a sporty driving style with
high cornering speeds or high rates of
acceleration.
R on vehicles with a trailer tow hitch, the
electrical connection to the trailer has been
correctly established.
R ESP ®
is deactivated.
R the transmission is not in position D.
R a loss of tyre pressure or a defective tyre
has been detected and displayed.
Active Lane Keeping Assist does not detect
road and traffic conditions. An inappropriate
brake application may be interrupted at any
time if:
R you steer slightly in the opposite direction.
R you use a turn signal.
R you clearly brake or accelerate.
Al ane-correcting brake applicatio nis inter-
rupted automatically if:
R a driving safety system intervenes, such as
ESP ®
, PRE-SAFE ®
Brake or Active Blind
Spot Assist.
R lane markings can no longer be recognised.
Activating Active Lane Keeping Assist Example: vehicles featuring automatic transmis-
sion with a DIRECT SELECT lever X
Switch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard or
Adaptive (Y
page 257).
Symbol :appears in the multifunction
display.
If you are driving faster than 60km/h and
lane markings are detected, symbol :is
highlighted. Active Lane Keeping Assist is
ready for use.
If Standard is selected, no warning vibra-
tion 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 ®
.
If Adaptive is selected, no warning vibra-
tion 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.
Towing atrailer
If you attach a trailer, make sure tha tyou have
correctly established the electrical connec-
tion. This can be accomplished by checking
the trailer lighting. Towing
atrailer Important safety notes
G
WARNING
The braking syste mcan overheat if you leave
your foo tonthe brake pedal while driving.
This increases the braking distance and could
even cause the braking system to fail. There
is a risk of an accident. 234
Towing
atrailerDriving an d parking 

Safety systems
Display messages Possible causes/consequences and
M Solutions
!÷
currently unavail‐
able See Owner's
Manual ABS (Anti-lock Braking System), ESP
®
(Electronic Stability Pro-
gram), BAS (Brake Assist), PRE-SAFE ®
, the HOLD function, hill
start assist and ESP ®
trailer stabilisation are temporarily unavail-
able.
The adaptive brake lights, BAS PLUS and PRE-SAFE ®
Brake may
also have failed.
In addition, the ä,åand! warning lamps light up in
the instrument cluster.
ATTENTION ASSIST is deactivated.
For example, the on-board voltage may be insufficient.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-
ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
The danger of skidding and having an accident increases.
X Drive on carefully.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. !÷
inoperative See
Owner's Manual ABS, ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist
and ESP ®
trailer stabilisation are unavailable due to a malfunction.
The adaptive brake lights, BAS PLUS and PRE-SAFE ®
Brake may
also have failed.
In addition, the J,ä,åand! warning lamps light
up in the instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example. Display messages
269On-board computer and displays Z 

Display messages Possible causes/consequences and
M Solutions
T!
÷
inoperative See
Owner's Manual EBD (electronic brake force distribution), ABS, ESP
®
, BAS, PRE-
SAFE ®
, the HOLD function ,hill start assist and ESP ®
trailer stabi-
lisatio nare unavailable due to a malfunction.
The adaptive brake lights, BAS PLUS and PRE-SAFE ®
Brake may
also have failed.
In addition, the ä,åand! warning lamps light up in
the instrument cluster and a warning tone sounds.
G WARNING
The brake system continues to function normally, but withou tthe
functions listed above. The front and rear wheels could therefore
lock if you brake hard, for example.
The steerability and braking characteristics may be severely affec-
ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
The danger of skidding and having an accident increases.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. J
Release parking
brake You are driving with the parking brake applied.
Awarning tone also
sounds.
X Release the parking brake. J
Brake immediately or
Vehicles with manual transmission
:with the HOL Dfunction acti-
vated, you have either:
R opened the driver's door and released the seat belt or
R switched off the engine or
R opened the bonnet.
At one may also sound at regular intervals. If you attempt to lock
the vehicle, the tone becomes louder.
You cannot start the engine.
X Paying attention to the traffic situation, immediately depress the
brake pedal firmly and hold until the display message disap-
pears.
X Secure the vehicle against rolling away (Y page 183).
You can restart the engine. Display messages
271On-board computer and displays Z 

Display messages Possible causes/consequences and
M Solutions
Â
Remove starting
button, then
insert key The KEYLESS-GO key is no
tcontinually detected.
KEYLESS-GO is temporarily malfunctioning or is defective. Awarn-
ing tone also sounds.
X Insert the key into the ignition lock and turn it to the desired
position.
X Visi taqualified specialist workshop. Â
Close doors to
lock vehicle At least one door is open.
Awarning tone also sounds.
X Close all doors and loc kthe vehicle again. Indicator and warning lamps in the
instrument cluster
Warning and indicator lamps over-
view
L Dipped-beam headlamps
(Ypage 126)
T Side lamps (Y page 127)
K Main-beam headlamps
(Ypage 129)
#! Turn signals (Y page 128)
R Rear foglamp (Y page 127)
ü Seat belts (Y page 299)
J Brakes (Ypage 300)
! ABS (Ypage 301)
ä ESP®
(Y page 302)
å ESP®
OFF (Y page 302)
M SPORT handling mode in AMG
vehicles (Ypage 303)
6 SRS (Ypage 304)
; Engine diagnostics
(Ypage 305)
8 Reserve fuel (Y page 305)
? Coolant (Ypage 305)
· Distance warning signal
(Ypage 307) %
Diesel engine: preglow
(Ypage 163)
h Tyre pressure monitor
(Ypage 308) 298
Indicator and warning lamps in the instrument clusterOn-board computer and displays 

Problem Possible causes/consequences and
M Solutions
!
The yellow ABS warning
lamp is lit while the
engine is running. ABS (Anti-lock Brake System) has been deactivated due to a fault.
For this reason, BAS (Brake Assist), BAS PLUS, ESP ®
(Electronic
Stability Program), PRE-SAFE ®
,P RE-SAFE ®
Brake ,the HOLD func-
tion, hill start assist, the adaptive brake lights and ESP ®
trailer
stabilisation are also deactivated, for example.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-
ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
The danger of skidding and having an accident increases.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic trans-
mission, will not be available. Indicator and warning lamps in the instrument cluster
301On-board computer and displays Z