Assist MERCEDES-BENZ C-Class SEDAN 2012 W204 Owner's Guide

GWARNING
Make sure that you do not endanger other
road users when you apply the brakes.
You can find a description of Brake Assist
(BAS) on ( Y page 59) or of BAS PLUS on
( Y page 60).
High-performance brake system for
AMG vehicles
The high-performance brake system is
installed only on the C 63 AMG.
GWARNING
New vehicle brake pads and discs, and
replacement brake pads and discs may take
several hundred miles of driving until they
provide optimum braking efficiency. Until that
time, you may need to use increased brake
pedal pressure while braking. Please be aware
of this and adjust your driving and braking
accordingly during this break-in period.
Excessive high-demand braking will cause
correspondingly high brake wear. Please be
attentive to the brake warning lamp in the
instrument cluster and brake condition
messages in the multifunction display.
Especially for high performance driving, it is
important to maintain and have the brake
system checked regularly.
The high-performance brake system is
designed for heavy loads. This may lead to
noise when braking. This will depend on:
R speed
R braking force
R environmental conditions, such as
temperature and humidity
The wear of individual components of the
brake system, such as the brake pads/linings
or brake discs, depends on the individual
driving style and operating conditions.
For this reason, it is impossible to state a
mileage that will be valid under all
circumstances. An aggressive driving style
will lead to high wear. You can obtain further
information about this from your authorized
Mercedes-Benz Center.
Driving on wet roads
Hydroplaning
If water has accumulated to a certain depth
on the road surface, there is a danger of
hydroplaning occurring, even if:
R you drive at low speeds.
R the tires have adequate tread depth.
For this reason, in the event of heavy rain or
in conditions in which hydroplaning can occur
you must drive in the following manner:
R reduce your speed
R avoid ruts
R brake carefully
Driving on flooded roads
! Do not drive through flooded areas.
Check the depth of any water before driving
through it. Drive slowly through standing
water. Otherwise, water may enter the
vehicle interior or the engine compartment.
This can damage the electronic
components in the engine or the automatic
transmission. Water can also be drawn in
by the engine's air suction nozzles and this
can cause engine damage.
Winter driving
General notes
GWARNING
If the vehicle becomes trapped in snow,
ensure that snow is kept away from the
exhaust pipe and from around the vehicle as
long as the engine is running. Otherwise,
poisonous carbon monoxide (CO) may enter
the vehicle, resulting in loss of consciousness
and even death.
158Driving tipsDriving and parking

To assure sufficient fresh air ventilation, open
a window slightly on the side of the vehicle
not facing the wind.
At the onset of winter, have your vehicle
winterproofed at a qualified specialist
workshop, e.g. at an authorized Mercedes-
Benz Center.
Observe the notes in the "Winter operation"
section ( Y page 312).
Driving with summer tires
Observe the notes in the "Winter operation"
section ( Y page 312).
Slippery road surfaces
GWARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point do not guarantee that the road
surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges.
GWARNING
On slippery road surfaces, never downshift in
order to obtain braking action. This could
result in drive wheel slip and reduced vehicle
control. Your vehicle's ABS will not prevent
this type of loss of control.
Drive particularly carefully on slippery road
surfaces. Avoid sudden acceleration, steering
and braking maneuvers. Do not use cruise
control or DISTRONIC PLUS.
If the vehicle threatens to skid or cannot be
stopped when moving at low speed:
XShift the transmission to position N.
i
For more information on driving with
snow chains, see ( Y page 313).
GWARNING
Make sure that you do not endanger other
road users when you apply the brakes.
Driving systems
Cruise control
Important safety notes
Cruise control maintains a constant road
speed for you. It brakes automatically in order
to avoid exceeding the set speed. On long and
steep downhill gradients, especially if the
vehicle is laden, you must select shift range
1 , 2 or 3 in good time. By doing so, you will
make use of the braking effect of the engine,
which relieves the load on the brake system
and prevents the brakes from overheating
and wearing too quickly.
Use cruise control only if road and traffic
conditions make it appropriate to maintain a
steady speed for a prolonged period. You can
set any road speed above 20 mph
(30 km/h).
GWARNING
The cruise control is a convenience system
designed to assist the driver during vehicle
operation. The driver is and must always
remain responsible for the vehicle's speed
and for safe brake operation.
Only use the cruise control if the road, traffic,
and weather conditions make it advisable to
travel at a constant speed.
R The use of the cruise control can be
dangerous on winding roads or in heavy
traffic because conditions do not allow safe
driving at a constant speed.
R The use of the cruise control can be
dangerous on slippery roads. Rapid
changes in tire traction can result in wheel
spin and loss of control.
R Deactivate the cruise control when driving
in fog.
The "Resume" function should only be
operated if the driver is fully aware of the
previously set speed and wishes to resume
this particular preset speed.
Driving systems159Driving and parkingZ

If you want DISTRONIC PLUS to assist you,
the radar sensor system must be activated
( Y page 208) and operational.
If there is no vehicle driving in front of you,
DISTRONIC PLUS functions like cruise
control at a speed range between 20 mph
(Canada: 30 km/h) and 120 mph
(Canada: 200 km/h). If a vehicle is driving in
front of you, it functions at a speed range
between 0 mph (0 km/h) and 120 mph
(Canada: 200 km/h).
Do not use DISTRONIC PLUS while driving on
roads with steep gradients.
As DISTRONIC PLUS transmits radar waves,
it can resemble the radar detectors of the
responsible authorities. You can refer to the
applicable section in the Operator's Manual if
there are any questions concerning this.
i USA only:
This device has been approved by the FCC
as a “Vehicular Radar System”. The radar
sensor is intended for use in an automotive
radar system only. Removal, tampering, or
altering of the device will void any
warranties, and is not permitted by the
FCC. Do not tamper with, alter, or use in
any non-approved way.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
i Canada only: This device complies with
RSS-210 of Industry Canada. Operation is
subject to the following two conditions:
1. This device may not cause interference,
and
2. this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Removal, tampering, or altering of the
device will void any warranties, and is not
permitted. Do not tamper with, alter, or use
in any non-approved way.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.GWARNING
The DISTRONIC PLUS adaptive cruise control
is not a substitute for active driving
involvement. It does not react to pedestrians
or on stationary objects, nor does it recognize
or predict the curvature and lane layout or the
movement of preceding vehicles. The
DISTRONIC PLUS can only apply a maximum
of 40% of the vehicle's braking power.
The DISTRONIC PLUS may not detect narrow
vehicles possibly driving in front of you, such
as motorcycles and vehicles driving in an
offset formation.
It is the driver's responsibility at all times to
be attentive to the road, weather and traffic
conditions. Additionally, the driver must
provide the steering, braking and other driving
inputs necessary to remain in control of the
vehicle.
High-frequency sources such as toll stations,
speed measuring systems etc. can cause the
DISTRONIC PLUS system to temporarily
cease functioning.
GWARNING
The DISTRONIC PLUS cannot take road and
traffic conditions into account. Only use the
DISTRONIC PLUS if the road, weather and
traffic conditions make it advisable to travel
at a constant speed.
GWARNING
Use of the DISTRONIC PLUS can be
dangerous on slippery roads. Rapid changes
in tire traction can result in wheel spin and
loss of control.
The DISTRONIC PLUS does not function in
adverse sight and distance conditions. Do not
use the DISTRONIC PLUS during conditions of
fog, heavy rain, snow or sleet.
162Driving systemsDriving and parking

you determine by the position of the
accelerator pedal.
Activating when driving towards a
stationary vehicle
If the vehicle in front of you is stationary, you
can only activate DISTRONIC PLUS once your
vehicle is stationary as well.XBriefly pull the cruise control lever towards
you ?, or briefly press up : or down ;.
DISTRONIC PLUS is selected.
i DISTRONIC PLUS can only be activated at
under 20 mph (30 km/h) if a vehicle in front
has been detected. Therefore, the
DISTRONIC PLUS distance display in the
instrument cluster should be activated
( Y page 204).
XKeep the cruise control lever pressed
up : or down ; until the desired speed
is set.
i You can use the cruise control lever to set
the stored speed and the control on the
cruise control lever to set the specified
minimum distance ( Y page 168).
Pulling away
XIf the vehicle in front pulls away: remove
your foot from the brake pedal.XBriefly pull the cruise control lever towards
you ?.
or
XAccelerate briefly.
Your vehicle pulls away and adapts its
speed to that of the vehicle in front.
Driving
If there is no vehicle in front, DISTRONIC
PLUS operates in the same way as cruise
control.
If a slower-moving vehicle is detected in front,
DISTRONIC causes your vehicle to brake. This
maintains the preset distance to the vehicle
in front.
If DISTRONIC PLUS detects a faster-moving
vehicle in front, it increases the driving speed
of your vehicle, but only up to the desired
speed you have stored.GWARNING
If you depress the brake, DISTRONIC PLUS is
deactivated unless your vehicle is stationary.
DISTRONIC PLUS then no longer brakes your
vehicle. In such cases, control the distance
from vehicles travelling in front with the brake
alone. You could otherwise cause an accident
and thereby injure yourself and others. The
driver remains fully responsible for the
vehicle's distance from other vehicles, the
speed being driven and for braking in good
time.
Changing lanes
If you wish to change to the passing lane (in
left-hand-drive vehicles, the passing lane is
the left-hand lane), DISTRONIC PLUS
supports you if:
R you are driving faster than 40 mph
(60 km/h).
R DISTRONIC PLUS is maintaining the
distance to a vehicle in front.
R you switch on the appropriate turn signals.
R DISTRONIC PLUS does not detect a danger
of collision.
If these conditions are met, your vehicle is
accelerated. Acceleration will be interrupted
if changing lanes takes too long or if the
distance between your vehicle and the
vehicle in front becomes too small.
GWARNING
DISTRONIC PLUS and Active Blind Spot Assist
are only aids designed to assist driving.
They do not relieve you of the responsibility
of paying attention. The driver remains fully
responsible for the vehicle's distance from
other vehicles, the vehicle's speed and for
braking in good time. Always pay attention to
traffic conditions and your surroundings.
Otherwise, you may fail to recognize dangers
in time, cause an accident and injure yourself
and others.
Driving systems165Driving and parkingZ

Setting the specified minimum distance
You can set the specified minimum distance
for DISTRONIC PLUS by varying the time span
between one and two seconds. With this
function, you can set the minimum distance
that DISTRONIC PLUS keeps to the vehicle in
front, dependent on vehicle speed. You can
see this distance in the multifunction display
( Y page 168).
GWARNING
It is up to the driver to exercise discretion to
select the appropriate setting given road
conditions, traffic, driver's preferred driving
style and applicable laws and driving
recommendations for safe following distance.
XTo increase: turn control ; in direction
= .
DISTRONIC PLUS then maintains a greater
distance between your vehicle and the
vehicle in front.XTo decrease: turn control ; in
direction :.
DISTRONIC PLUS then maintains a shorter
distance between your vehicle and the
vehicle in front.
i Make sure that you maintain a sufficient
and safe distance from the vehicle in front.
Adjust the distance to the vehicle in front if
necessary.
DISTRONIC PLUS displays in the
speedometer
When DISTRONIC PLUS is activated, one or
two segments ; in the set speed range light
up.
i For design reasons, the speed displayed
in the speedometer may differ slightly from
the speed set for DISTRONIC PLUS.
If DISTRONIC PLUS detects a vehicle in front,
segments ; between speed of the vehicle in
front : and stored speed = light up.
DISTRONIC PLUS displays in the
multifunction display
General notes
You can select the distance display in the
Assistance menu ( Y page 204) of the on-
board computer.
Display when DISTRONIC PLUS is
deactivated
XSelect the Distance Display function
using the on-board computer
( Y page 204).
When DISTRONIC PLUS is deactivated, you
will see the following in the multifunction
display:
168Driving systemsDriving and parking

The calibration of the suspension depends
on:
R your driving style
R the road surface conditions
R your individual selection; see the following
description
If your vehicle is equipped with automatic
transmission, the dynamic handling package
with sports mode also includes steering
wheel paddle shifters ( Y page 145) with a
manual drive program ( Y page 147).
Example: position of dynamic handling package
with sports mode button
XStart the engine.
Sports tuning
The firmer setting of the suspension tuning in
sports mode ensures even better contact
with the road. Select this mode when
employing a sporty driving style, e.g. on
winding country roads.
Your selection remains stored until you
switch off the engine.
XPress button ;.
Indicator lamp : lights up. Sports
suspension tuning is selected. Depending
on the engine output, the accelerator pedal
is more responsive. On vehicles with
automatic transmission, drive program S is
selected.Comfort tuning
In Comfort mode, the driving characteristics
of your vehicle are more comfortable. Select
this mode if you prefer a more comfortable
driving style, but also when driving fast on
straight roads, e.g. highways.
XPress button ;.
Indicator lamp : goes out. Comfortable
suspension tuning is selected. On vehicles
with automatic transmission, drive
program E is selected.
HOLD function
General notes
The HOLD function can assist the driver in the
following situations:
R when pulling away, especially on steep
slopes
R when maneuvering on steep slopes
R when waiting in traffic
The vehicle is kept stationary without the
driver having to depress the brake pedal.
The braking effect is canceled and the HOLD
function deactivated when you depress the
accelerator pedal to pull away.
Activation conditions
You can activate the HOLD function if:
R the vehicle is stationary.
R the engine is running.
R the driver's door is closed or your seat belt
is fastened.
R the parking brake is not applied.
R the hood is closed.
R the transmission is in position D, R or N.
R DISTRONIC PLUS is deactivated.
172Driving systemsDriving and parking

You are responsible for safety at all times and
must continue to pay attention to the
immediate surroundings when parking and
maneuvering. This includes the area behind,
in front of, and beside the vehicle. Otherwise
you could endanger yourself and/or others.GWARNING
The rear view camera will not function or will
not fully function if:
R the trunk lid is open
R it is raining or snowing strongly or if it is
foggy
R it is night or if you are parking/
maneuvering your vehicle in a very dark
area
R a very bright white light is affecting the
camera
R the immediate vicinity is illuminated with
fluorescent light (the display of the
COMAND system can flicker)
R temperature changes abruptly, for example
if you drive out of the cold into a heated
garage (condensation on the lens)
R the camera lens is dirty or covered
R the rear of your vehicle is damaged
In this case, have the position and the
setting of the camera checked at a
specialist workshop. Mercedes-Benz
recommends that you consult a Mercedes-
Benz Center for this purpose.
Do not use the rear view camera in these
situations. You could otherwise injure
yourself and other people and/or cause
damage - including damage to your vehicle -
while parking/maneuvering.
Activating the rear view camera
XMake sure that the SmartKey is in position
2 in the ignition lock.XMake sure that the "rear view camera"
function is selected in COMAND (see theseparate operating instructions for
COMAND).XEngage reverse gear.
The area behind the vehicle is shown in the
COMAND display.
ATTENTION ASSIST
Important safety notes
ATTENTION ASSIST helps you during long,
monotonous journeys such as on freeways
and interstate highways. It is active in the
range between 50 mph (80 km/h) and
112 mph (180 km/h).
If ATTENTION ASSIST detects typical
indicators of fatigue or increasing lapses in
concentration on the part of the driver, it
suggests you take a break.
GWARNING
ATTENTION ASSIST is only an aid and may
detect your tiredness or lapses in
concentration too late or not at all. It is not a
substitute for a well-rested and attentive
driver.
Fatigue may cause you to recognize
hazardous situations too late, misjudge a
situation or react more slowly. For this
reason, make sure you feel rested before you
begin driving and during your journey. Make
sure that you take regular breaks in time,
particularly on long journeys. Otherwise, you
may fail to recognize dangers in time, cause
an accident and injure yourself and others.
ATTENTION ASSIST assesses your level of
fatigue or lapses in concentration by taking
the following criteria into account:
R your personal driving style, e.g. steering
characteristics
R driving conditions, e.g. time, driving time
182Driving systemsDriving and parking

The functionality of ATTENTION ASSIST is
restricted and warnings may be delayed or
not occur at all:
R if the road condition is poor, e.g. if the
surface is uneven or if there are potholes
R if there is a strong side wind
R if you have adopted a sporty driving style
with high cornering speeds or high rates of
acceleration
R if you predominantly drive at speeds under
50 mph (80 km/h) or over 112 mph
(180 km/h)
R if you are currently using COMAND or
making a telephone call with it
R if the time has been set incorrectly
R in active driving situations, such as when
you change lanes or change your speed
Warning and display messages in the
multifunction displayXActivate ATTENTION ASSIST using the on-
board computer ( Y page 205).
Symbol : appears in the multifunction
display.
If ATTENTION ASSIST is active, you will be
warned no sooner than 20 minutes after your
journey has begun. You will then hear an
intermittent warning tone twice, and the
Attention Assist: Drowsiness
Detected message appears in the
multifunction display.
XIf necessary, take a break.XPress a to confirm the message.
On long journeys, take regular breaks in good
time to allow yourself to rest properly. If you
do not take a break and ATTENTION ASSIST
still detects typical indicators of fatigue or
increasing lapses in concentration, you will be
warned again after 15 minutes at the earliest.
ATTENTION ASSIST is reset when you
continue your journey and starts assessing
your tiredness again if:
R you switch off the engine.
R you take off your seat belt and open the
driver's door, e.g. for a change of drivers or
to take a break.
Lane Tracking package
General notes
The Lane Tracking package consists of Blind
Spot Assist ( Y page 183) and Lane Keeping
Assist ( Y page 185).
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
approximately 20 mph (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. Blind Spot Assist uses
sensors in the rear bumper for monitoring
purposes.
GWARNING
Blind Spot Assist is only an aid designed to
assist driving. It may fail to detect some
vehicles and is no substitute for attentive
driving.
Blind Spot Assist cannot detect road and
traffic conditions. It may fail to detect narrow
vehicles, such as motorcycles or bicycles, or
may only detect them too late.
Monitoring may be affected by dirty sensors,
strong spray or poor visibility caused by snow,
Driving systems183Driving and parkingZ

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
recognize dangers in time, cause an accident
and injure yourself and others.
i USA only:
This device has been approved by the FCC
as a “Vehicular Radar System”. The radar
sensor is intended for use in an automotive
radar system only. Removal, tampering, or
altering of the device will void any
warranties, and is not permitted by the
FCC. Do not tamper with, alter, or use in
any non-approved way.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
For Blind Spot Assist to assist you when
driving, the radar sensor system must be
activated ( Y page 208) and operational.
Monitoring range of the sensors
Blind Spot Assist monitors the area shown in
the figure up to 10 ft (3 m) behind and
immediately adjacent to your vehicle.GWARNING
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. There is no display and no
warning.
If the lanes are very wide, it may not be
possible to monitor the complete width of the
neighboring 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
that edge of their lane which is furthest away
from your vehicle.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
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 the vehicles are driving on the
inner side of their lane.
Due to the nature of the system:
R warnings may be issued in error when
driving close to crash barriers or similar
solid lane borders.
R warnings may be interrupted when driving
alongside long vehicles, such as trucks, for
a prolonged time.
The two sensors for Blind Spot Assist are
integrated into the sides of the rear bumper.
Make sure that the bumper is free from dirt,
ice or slush around the sensors. The rear
sensors must not be covered, for example by
bicycle racks or overhanging loads. Following
a severe impact or in the event of damage to
the bumpers, have the function of the radar
sensors checked at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz
Center. Blind Spot Assist may otherwise not
work properly.184Driving systemsDriving and parking

Indicator and warning display:Yellow indicator lamp/red warning lamp
When Blind Spot Assist is activated, indicator
lamp : lights up yellow in the exterior
mirrors up to a vehicle speed of 20 mph
(30 km/h). When the vehicle speed exceeds
20 mph (30 km/h), the indicator lamp goes
out and Blind Spot Assist is ready for use.
When your speed exceeds approximately
20 mph (30 km/h), warning lamp : lights up
red on the corresponding side whenever a
vehicle is detected in the blind spot
monitoring range. This warning is always
given when a vehicle enters the blind spot
monitoring range from behind or from the
side. When you are passing another vehicle,
the warning is emitted only if the difference
in speed is less than 7 mph (12 km/h).
The yellow indicator lamp goes out if reverse
gear is engaged. In this event, Blind Spot
Assist is no longer active.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.
GWARNING
Blind Spot Assist is not active at speeds under
approximately 20 mph (30 km/h). The
indicator lamps in the exterior mirrors are
yellow. Vehicles in the monitoring range are
then not indicated.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
Collision warning
If a vehicle is detected in the monitoring range
of Blind Spot Assist and you switch on the turn
signal, a double warning tone sounds. Red
warning lamp : flashes. If the turn signal
remains on, detected vehicles are indicated
by the flashing of red warning lamp :. There
are no further warning tones.
Switching on Blind Spot AssistXMake sure that the radar sensor system
( Y page 208) and Blind Spot Assist
( Y page 205) are activated in the on-board
computer.XTurn the SmartKey to position 2 in the
ignition lock.
Warning lamps : light up red in the
exterior mirrors for approximately 1.5
seconds and then turn yellow.
Lane Keeping Assist
Important safety notes
Lane Keeping Assist monitors the area in
front of your vehicle by means of a camera at
the top of the windshield. Lane Keeping Assist
detects lane markings on the road and warns
you before you leave your lane
unintentionally.
:Lane Keeping Assist camera
If you have chosen the Display Unit
Speed-/Odometer (Y page 206) function in
the on-board computer and select km as the
unit of measurement, Active Lane Keeping
Assist is active from speeds of 60 km/h. If
Driving systems185Driving and parkingZ