brakes MERCEDES-BENZ S-Class 2012 W221 User Guide

or yellow. Always secure the vehicle against
rolling away before leaving it.
! Always switch the ignition off and take the
key with you when leaving the vehicle.
Automatic engine switch-off
The ECO start/stop function switches the
engine off automatically if the vehicle is
braked to a standstill and the brake remains
depressed with the transmission in position
D or N.
i You can still activate the HOLD function
when the vehicle is stationary, even if the
engine has been switched off
automatically. It is then not necessary to
continue applying the brakes during the
automatic stop phase. When you depress
the accelerator pedal, the engine starts
automatically and the braking effect of the
HOLD function is deactivated. Depress the
accelerator pedal carefully, as the engine
must be started first.
The engine is only switched off if:
R the outside temperature is within the range
which is suitable for the system.
R the engine is at normal operating
temperature.
R the set temperature for the vehicle interior
has been reached.
R the battery is sufficiently charged.
R the system detects that the windshield is
not fogged up when the air-conditioning
system is switched on.
R the hood is closed.
R no engine-relevant diagnostics are active.
R the driver's door is closed and the seat belt
is fastened.
Automatic engine start
The engine is started automatically if you:
R release the brake pedal when HOLD is not
activated and the transmission is in
position D or N
R shift the transmission to position R
R depress the accelerator pedal
R switch off the ECO start/stop function or
switch to drive program S or M
R unfasten your seat belt or open the driver's
door
The engine is also started automatically if:
R the vehicle starts to roll.
R the brake system requires this.
R the system detects moisture on the
windshield when the air-conditioning
system is switched on.
R the temperature in the vehicle interior
deviates from the set range.
R the charge level of the battery is too low.
Deactivating/activating the ECO start/
stop function
General information
You can deactivate and activate the ECO
start/stop function using COMAND
( Y page 261).
i You can also use the programmable
button ( Y page 120) to activate and
deactivate the ECO start/stop function if
you have assigned this function to the
button.
Deactivating
XDeactivate the ECO start/stop function
using COMAND ( Y page 261):
The ¤ ECO symbol goes out and the
Stop/Start deactivated display
message is shown in the multifunction
display.
i If drive program S or M has been selected,
the ECO start/stop function is always
deactivated.
Driving307Driving and parkingZ

ANeutral
Do not shift the transmission to N
while driving. The transmission
could otherwise be damaged.
No power is transmitted from the
engine to the drive wheels.
Releasing the brakes will allow you
to move the vehicle freely, e.g. to
push it or tow it.
If ESP ®
is deactivated or faulty:
only shift the transmission to
position N if the vehicle is in danger
of skidding, e.g. on icy roads.
! Rolling in neutral N can damage
the drive train.7Drive
The automatic transmission
changes gear automatically. All
forward gears are available.
Changing gear
The automatic transmission shifts to the
individual gears automatically when it is in
transmission position D. This automatic
gearshifting behavior is determined by:
R a shift range restriction, if selected
R the selected drive program
E/S or, for AMG vehicles,
C/S/M (Y page 314)
R the position of the accelerator pedal
R the road speed
Driving tips
Kickdown
Use kickdown for maximum acceleration.
XVehicles for USA except AMG vehicles:
fully depress the accelerator pedal.
The transmission shifts to a lower gear
depending on the engine speed.XVehicles for Canada except AMG
vehicles: depress the accelerator pedal
beyond the pressure point.
The transmission shifts to a lower gear
depending on the engine speed.
Rocking the vehicle free
Rocking the vehicle free by shifting back and
forth between transmission positions D and
R can help to free a vehicle that has become
stuck in mud or snow. The engine
management system of the vehicle limits
shifting back and forth between transmission
positions D and R to a maximum speed of
5 mph (9 km/h). To shift back and forth
between transmission positions D and R,
move the selector lever up and down beyond
the pressure point.
Working on the vehicle
GWARNING
When working on the vehicle, engage the
electronic parking brake and shift the
automatic transmission into park position P.
Otherwise the vehicle could roll away which
could result in an accident and/or serious
personal injury.
Automatic transmission313Driving and parkingZ

1 in the ignition lock or if the ignition has
been switched on using the Start/Stop
button.
Engaging the electric parking brake
automatically
The electric parking brake is automatically
applied if HOLD or DISTRONIC PLUS brakes
the vehicle until it is stationary and at least
one of the following conditions is fulfilled:
R the engine is switched off.
R the driver's door is open and the seat belt
is not fastened.
R the hood is released.
R the trunk lid is opened while the automatic
transmission is in position R.
R the vehicle is stationary for a lengthy
period.
The red F (USA only) or ! (Canada
only) indicator lamp in the instrument cluster
lights up.
i In addition to the electric parking brake,
P may also be engaged automatically.
Releasing the electric parking brake
automatically
The electric parking brake is released
automatically when the following conditions
are simultaneously fulfilled:
R the engine is running.
R the automatic transmission is in position
D or R.
R the hood is closed.
R your seat belt is fastened.
R you depress the accelerator pedal.
If the automatic transmission is in position
R , the trunk lid must be closed.
If your seat belt is not fastened, the following
conditions must be fulfilled to automatically
release the electric parking brake:
R the driver's door is closed.
R you shift out of P or you have previously
driven faster than 3 km/h.
R you have shifted out of P or you have
previously driven faster than 2 mph
(3 km/h).
Emergency braking
The vehicle can also be braked during an
emergency using the electric parking brake.
XWhile driving, push handle : of the electric
parking brake ( Y page 324).
i
The vehicle is braked as long as you keep
the handle of the electric parking brake
pressed. The longer the electric parking
brake handle is depressed, the greater the
braking force.
During braking:
R a warning tone sounds.
R the Please Release Parking Brake
message appears.
R the red F (USA only) or ! (Canada
only) indicator lamp in the instrument
cluster lights up.
When the vehicle has been braked to a
standstill, the electric parking brake is
engaged.
Parking the vehicle for a long period
If you leave the vehicle parked for longer than
four weeks, the battery may be damaged by
exhaustive discharge.
XConnect a trickle charger.
i You can obtain information about trickle
chargers from a qualified specialist
workshop, e.g. an authorized Mercedes-
Benz Center.
Parking325Driving and parkingZ

Steering and braking requires significantly
more effort and you could lose control of the
vehicle and cause an accident as a result.
Do not turn off the engine while the vehicle is
in motion.
Exhaust checkGWARNING
Inhalation of exhaust gas is hazardous to your
health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause
unconsciousness and possible death.
Do not run the engine in confined areas (such
as a garage) which are not properly ventilated.
If you think that exhaust gas fumes are
entering the vehicle while driving, have the
cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one
window fully open at all times.
Certain engine systems are designed to keep
the level of poisonous components in exhaust
fumes within legal limits.
These systems only work at peak efficiency
when they are maintained exactly in
accordance with the manufacturer's
specifications. For this reason, all work on the
engine must be carried out only by qualified
and authorized Mercedes-Benz technicians.
The engine settings must not be changed in
any circumstances. Furthermore, all specific
service work must be carried out at regular
intervals and in accordance with the
Mercedes-Benz service requirements. Details
can be found in the Service Booklet.
Brakes
Important safety notes
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.GWARNING
Make sure that you do not endanger other
road users when you apply the brakes.
Downhill gradients
! On long and steep gradients, you must
reduce the load on the brakes by shifting
early to a lower gear. This allows you to take
advantage of the engine braking effect and
helps avoid overheating and excessive
wear of the brakes.
When you take advantage of the engine
braking effect, a drive wheel may not turn
for some time, e.g. on a slippery road
surface. This could cause damage to the
drive train. This type of damage is not
covered by the Mercedes-Benz warranty.
Heavy and light loads
GWARNING
Depressing the brake pedal constantly results
in excessive and premature wear to the brake
pads.
It may also cause the brakes to overheat,
seriously impairing their effectiveness. It may
then not be possible to stop the vehicle in
sufficient time to avoid an accident.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately, but
drive on for a short while. This allows the
airflow to cool the brakes more quickly.
Wet roads
GWARNING
After driving in heavy rain for some time
without applying the brakes or through water
deep enough to wet brake components, the
first braking action may be somewhat
reduced. You have to depress the brake pedal
Driving tips327Driving and parkingZ

more firmly. Maintain a safe distance from
vehicles in front.
After driving on a wet road or having the
vehicle washed, brake firmly while paying
attention to the traffic conditions. This will
warm up the brake discs, thereby drying them
more quickly and protecting them against
corrosion.
Limited braking performance on salt
treated roadsGWARNING
The layer of salt on the brake discs and the
brake pads/linings may cause a delay in the
braking effect, resulting in a significantly
longer braking distance, which could lead to
an accident.
To avoid this danger, you should:
R occasionally brake carefully, without
putting other road users at risk, when you
are driving on salted roads. This helps to
remove any salt that may have started to
build up on the brake discs and the brake
pads/linings.
R maintain a greater distance to the vehicle
ahead and drive with particular care.
R carefully apply the brakes at the end of a
trip and immediately after commencing a
new trip, so that salt residues are removed
from the brake discs.
Servicing the brakes
! If the red brake warning lamp lights up in
the instrument cluster and you hear a
warning tone while the engine is running,
the brake fluid level may be too low.
Observe additional warning messages in
the multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked
immediately. This work should be carried
out at an authorized Mercedes-Benz
Center.
All checks and maintenance work on the
brake system must be carried out at a
qualified specialist workshop. This work
should be carried out at an authorized
Mercedes-Benz Center.
Have the brake pads replaced and the brake
fluid renewed at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz
Center.GWARNING
If brake pads or brake fluid other than those
recommended are used, the braking
properties of the vehicle can be degraded to
an extent that safe braking is substantially
impaired. This could result in an accident.
! Vehicles with 4MATIC: function or
performance tests may only be carried out
on a 2-axle dynamometer. If you are
planning to have the vehicle tested on such
a dynamometer, contact an authorized
Mercedes-Benz Center to obtain further
information first. Otherwise, you could
damage the drive train or the brake system.
! Vehicles with 4MATIC: as the ESP®
system operates automatically, the engine
and the ignition must be switched off
(SmartKey in position 0 or 1 in the ignition
lock or Start/Stop button in position 0 or
1 ) when the electric parking brake is being
tested on a brake dynamometer.
Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake
system.
! Vehicles with 4MATIC: as the ESP®
system operates automatically, the engine
and the ignition system must be switched
off (SmartKey in position 0 or 1 in the
ignition lock or Start/Stop button in
position 0 or 1) when:
R testing the electric parking brake on a
brake dynamometer.
R you intend to have the vehicle towed with
one of the axles raised.
328Driving tipsDriving and parking

Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake
system.
If your brake system is subject only to
moderate loads, you should test the
functionality of your brakes at regular
intervals by pressing firmly on the brake pedal
at high speeds. This improves the grip of the
brake pads.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 70) or of BAS PLUS on
( Y page 70).
High-performance brake system for
AMG vehicles
The high-performance brake system is
installed only on the S 63 AMG and S 65 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
Driving tips329Driving and parkingZ

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.
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 492).
Driving with summer tires
Observe the notes in the "Winter operation"
section ( Y page 492).
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 493).
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.
330Driving systemsDriving and parking

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.
Cruise control lever:To switch on or to increase the speed;To switch on or to reduce the speed=To deactivate cruise control?To switch on with the current speed or
with the last stored speed
When you activate cruise control, the stored
speed is shown in the multifunction display
for five seconds and is indicated in the
speedometer by a triangle. The speedometer
dial lights up between the set speed and the
maximum speed.
Storing and maintaining the current
speed
You can store the current speed if you are
driving faster than 20 mph (30 km/h).
XAccelerate the vehicle to the desired
speed.XBriefly press the cruise control lever
up : or down ;.XRemove your foot from the accelerator
pedal.
Cruise control is activated. The vehicle
automatically maintains the speed.
i Cruise control may be unable to maintain
the stored speed on uphill gradients. The
stored speed is resumed when the gradient
evens out. Cruise control maintains the
stored speed on downhill gradients by
automatically applying the brakes.
Storing the current speed or calling up
the last stored speed
GWARNING
The set speed stored in memory should only
be set again if prevailing road conditions and
legal speed limits permit. Possible
acceleration or deceleration differences
arising from returning to the preset speed
could cause an accident and/or serious injury
to you and others.
XBriefly pull the cruise control lever towards
you ?.XRemove your foot from the accelerator
pedal.
The first time cruise control is activated, it
stores the current speed or regulates the
speed of the vehicle to the previously
stored speed.Driving systems331Driving and parkingZ

Setting a speedGWARNING
Keep in mind that it may take a brief moment
until the vehicle has made the necessary
adjustments.
Increase or decrease the set vehicle speed to
a value that the prevailing road conditions and
legal speed limits permit. Otherwise, sudden
and unexpected acceleration or deceleration
of the vehicle could cause an accident and/
or serious injury to you and others.
XPress the cruise control lever up : for a
higher speed or down ; for a lower speed.XKeep the cruise control lever pressed until
the desired speed is reached.XRelease the cruise control lever.
The new speed is stored.
i Cruise control is not deactivated if you
depress the accelerator pedal. For
example, if you accelerate briefly to
overtake, cruise control adjusts the
vehicle's speed to the last speed stored
after you have finished overtaking.
Making adjustments in 1 mph (Canada:
1 km/h) increments
XBriefly press the cruise control lever to the
pressure point, up : for a higher speed or
down ; for a lower speed.
The last speed stored is increased or
reduced.
Making adjustments in 5 mph (Canada:
10 km/h) increments
XBriefly press the cruise control lever
beyond the pressure point, up : for a
higher speed or down ; for a lower speed.
The last speed stored is increased or
reduced.Deactivating cruise control
There are several ways to deactivate cruise
control:
XBriefly press the cruise control lever
forwards =.
or
XBrake.
Cruise control is automatically deactivated if:
R you engage the electric parking brake.
R you are driving below 20 mph (30 km/h).
R ESP ®
intervenes or you deactivate ESP ®
.
R you shift the transmission to position N
while driving.
If cruise control is deactivated, you will hear
a warning tone. You will see the Cruise
Control Off message in the multifunction
display for approximately five seconds.
i The last speed stored is cleared when you
switch off the engine.
DISTRONIC PLUS
Important safety notes
DISTRONIC PLUS regulates the speed and
automatically helps you maintain the
distance to the vehicle detected in front. 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.
If a slower-moving vehicle is detected in front,
DISTRONIC PLUS causes your vehicle to
brake and maintain a preset distance to the
vehicle in front.
GWARNING
HYBRID vehicles: It is imperative that you read
the HYBRID Supplemental Operating
332Driving systemsDriving and parking

Instructions included in your vehicle literature
portfolio. You may otherwise not receive all
necessary safety information and warning for
the operation of your vehicle.GWARNING
The DISTRONIC PLUS requires familiarity with
its operational characteristics. We strongly
recommend that you review the following
information carefully before operating the
system.
GWARNING
When DISTRONIC brakes, the brake pedal is
pulled back (i.e. operated automatically). The
area around the pedal must not be blocked by
obstacles:
R do not place any objects in the footwell.
R ensure that floormats and carpets are fixed
securely. In particular, do not place several
floormats on top of one another.
R do not place your foot under the brake
pedal, as it could become trapped.
Non-compliance could lead you to cause an
accident in which you and/or others could be
seriously injured.
GWARNING
The DISTRONIC PLUS is a convenience
system. Its speed adjustment reduction
capability is intended to make cruise control
more effective and usable when traffic speeds
vary. It is not however, intended to, nor does
it, replace the need for extreme care.
The responsibility for the vehicle's speed,
distance to the preceding vehicle and, most
importantly, brake operation to ensure a safe
stopping distance, always remains with the
driver.
The DISTRONIC PLUS cannot take street and
traffic conditions into account.
Complex driving situations are not always
fully recognized by the DISTRONIC PLUS. This
could result in wrong or missing distance
warnings.
If you want DISTRONIC PLUS to assist you,
the radar sensor system must be activated
( Y page 387) 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.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
Driving systems333Driving and parkingZ