brakes MERCEDES-BENZ S550 2007 W221 User Guide

396 Controls in detailDriving systems
Setting the following distance in
DISTRONIC Plus
You can set the specified following dis-
tance for DISTRONIC Plus by varying the
time setting between 1.0 and 2.0 seconds.
Using this time setting and the current set
speed of your vehicle, DISTRONIC Plus cal-
culates and sets the required following dis-
tance to the vehicle ahead. The set
distance will be shown in the multifunction
display.The distance setting switch for the target
distance is located on the DISTRONIC Plus
lever.
1Distance setting switch for target dis-
tance
2To increase target distance
3To decrease target distance
Increasing distance
Increasing the distance setting causes
DISTRONIC Plus to maintain a greater fol-
lowing distance to the vehicle ahead.

Move distance setting switch 1 in di-
rection 2.
Warning!
G
DISTRONIC Plus switches off and releases
the brakes when the vehicle decelerates be-
low the minimum speed of 20 mph
(30 km / h) by operation of the system un-
less DISTRONIC Plus detects a vehicle di-
rectly ahead of you. At that time the driver
must apply the brakes in order to reduce ve-
hicle speed further or bring it to a stop.!
Setting the automatic transmission toN
while driving cancels the DISTRONIC Plus. How-
ever, the automatic transmission should not be
set toN while driving except to coast when the
vehicle is in danger of skidding (e.g. on icy
roads).
i
Depressing the accelerator pedal does not
deactivate DISTRONIC Plus. After brief accelera-
tion (e.g. for passing), DISTRONIC Plus will re-
sume the last speed set.
Warning!
G
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 recom-
mendations for safe following distance.

397 Controls in detail
Driving systems
Decreasing distance
Decreasing the distance setting causes
DISTRONIC Plus to maintain a shorter fol-
lowing distance to the vehicle ahead.
Move distance setting switch 1 in di-
rection 3.
Distance warning function
When DISTRONIC Plus is deactivated, this
function will continue to warn you when
recognizing a slower vehicle moving in
your vehicle’s path or a stationary object in
your vehicle’s path and the danger of a col-
lision exists:


The distance warning lampl in the
instrument cluster comes on.


An intermittent warning sounds.
If these warnings are issued, you must
brake manually to maintain a safe distance
and avoid a collision with the vehicle or
stationary object ahead.When pressing the brake pedal, the warn-
ing sound stops. The warning sound also
stops when the distance to the vehicle
ahead is sufficient again without applying
the brake pedal. In this case the distance
warning lampl also goes out.Activating and deactivating
The distance warning function can be acti-
vated or deactivated using the instrument
cluster control system (
page 252).
After the function has been activated,
: appears on the left-hand side of the
multifunction display.
Driving with DISTRONIC Plus
This section describes a number of driving
situations where special precaution is re-
quired on the part of the driver. Be pre-
pared to brake in such situations which will
deactivate the DISTRONIC Plus system.
Warning!
G
If the DISTRONIC Plus warning lampl in
the instrument cluster comes on while driv-
ing and/or an intermittent warning sounds,
immediate attention on the part of the driver
is required. As required by the traffic situa-
tion, apply the brakes and navigate around a
possible obstacle. However, do not drive by
relying on the distance warning function, as
this will result in an emergency braking ap-
plication. Especially depending on road sur-
face conditions and driver reaction, this will
not always enable you to avoid a collision.
Warning!
G
DISTRONIC Plus works to maintain the
speed selected by the driver unless a mov-
ing obstacle proceeding directly ahead of it
in the same travel direction is detected (e.g.
following another vehicle ahead of you at a
distance set by DISTRONIC Plus).


405 Controls in detail
Driving systems
Parktronic system*
Parktronic is an electronic parking aid with
ultrasonic sensors that helps you while
parking.
It visually and audibly indicates the relative
distance between the vehicle and an ob-
stacle.
Parktronic is automatically activated when
you switch on the ignition, release the
electric parking brake or start the engine
and engage gear D, R or N.The Parktronic system deactivates at
speeds over approximately 11 mph
(18 km/h). At lower speeds the Parktronic
system turns on again.
Parktronic is also switched off when you
engage gear P or secure the vehicle in
place with the electric parking brake and
switch off the engine.
The Parktronic system monitors the sur-
roundings of your vehicle with six sensors
in the front bumper and four sensors in the
rear bumper.
1Sensors in the front bumper (Only visi-
ble without DISTRONIC Plus*)Warning!
G
Parktronic is a supplemental system. It is
not intended to, nor does it replace, the
need for extreme care. The responsibility
during parking and other critical maneuvers
always rests with the driver.
Special attention must be paid to objects
with smooth surfaces or low silhouettes
(e.g. trailer couplings, painted posts, or road
curbs). Such objects may not be detected by
the system and can damage the vehicle.
The operational function of the Parktronic
system can be affected by dirty sensors, es-
pecially at times of snow and ice, see
“Cleaning the Parktronic* system sensors”
(page 538).
Warning!
G
Make sure no persons or animals are in the
area in which you are maneuvering. You
could otherwise injure them.i
Interference caused by other ultrasonic sig-
nals (e.g. working jackhammers, car wash, or the
air brakes of trucks) can cause the system to
send erratic indications, and should be taken
into consideration.

406 Controls in detailDriving systemsRange of the sensorsFront sensors
Rear sensorsMinimum distance
If the system detects an obstacle in this
range, all the distance warning segments
illuminate and you hear a warning signal. If
the obstacle is closer than the minimum
distance, the actual distance may no long-
er be indicated by the system.i
To function properly, the sensors must be
free of dirt, ice, snow and slush. Clean the sen-
sors regularly, being careful not to scratch or
damage the sensors, see “Cleaning the Park-
tronic* system sensors” (
page 538).
Center
approx. 40 in (100 cm)
Corners
approx. 24 in (60 cm)
Center
approx. 48 in (120 cm)
Corners
approx. 32 in (80 cm)
!
During parking maneuvers, pay special at-
tention to objects located above or below the
height of the sensors (e.g. street curbs, painted
posts, or trailer hitches etc.). The Parktronic sys-
tem will not detect such objects at close range
and damage to your vehicle or the object may re-
sult.
Ultrasonic signals from outside sources (e.g.
truck air brakes, car wash, or jackhammers) may
impair the operation of the Parktronic system.
Center
approx. 8 in (20 cm)
Corners
approx. 6 in (15 cm)

480 OperationDriving instructionsBrakesTo help prevent brake disk corrosion after
driving on wet road surfaces (particularly
salted roads), it is advisable to brake the
vehicle with considerable force prior to
parking. The heat generated serves to dry
the brakes.
If your brake system is normally only sub-
jected to moderate loads, you should occa-
sionally test the effectiveness of the
brakes by applying above-normal braking
pressure at higher speeds. This will also
enhance the grip of the brake pads.
Refer to the description of the Brake Assist
System (BAS) (
page 71).If the parking brake is released and the
brake warning lamp in the instrument clus-
ter stays on and there is no audible warn-
ing (EBP), the brake fluid level in the
reservoir is too low.
Brake pad wear or a leak in the system may
be the reason for low brake fluid in the res-
ervoir.
Have the brake system inspected immedi-
ately. Contact an authorized
Mercedes-Benz Center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
Mercedes-Benz Center.
Only install brake pads and brake fluid
recommended by Mercedes-Benz.
Warning!
G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components,
the first braking action may be somewhat
reduced and increased pedal pressure may
be necessary to obtain expected braking ef-
fect. Maintain a safe distance from vehicles
in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an acci-
dent.
Warning!
G
Make sure not to endanger any other road
users when carrying out these braking ma-
neuvers.

481 Operation
Driving instructions
After hard braking, it is advisable to drive
on for some time, rather than immediately
park, so that the air stream can cool down
the brakes faster.
Driving off
Apply the brakes to test them briefly after
driving off. Perform this procedure only
when the road is clear of other traffic.
Warm up the engine smoothly. Do not
place full load on the engine until the oper-
ating temperature has been reached.
When starting off on a slippery surface, do
not allow a drive wheel to spin for an ex-
tended period with the ESP
® switched off.
Doing so may cause serious damage to the
drivetrain which is not covered by the
Mercedes-Benz Limited Warranty.
Parking
Warning!
G
If other than recommended brake pads are
installed, or other than recommended brake
fluid is 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.!
When driving down long and steep grades,
relieve the load on the brakes by shifting into a
lower gear to use the engine’s braking power.
This helps prevent overheating of the brakes and
reduces brake pad wear.
When using the engine’s braking power, a drive
wheel may not spin for an extended period of
time, e.g. on slippery road surfaces. This may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited War-
ranty.
!
Simultaneously depressing the accelerator
pedal and applying the brake reduces engine
performance and causes premature brake and
drivetrain wear.
Warning!
G
Do not park this vehicle in areas where com-
bustible materials such as grass, hay or
leaves can come into contact with the hot
exhaust system, as these materials could be
ignited and cause a vehicle fire.
To reduce the risk of personal injury as a re-
sult of inadvertent vehicle movement, be-
fore turning off the engine and leaving the
vehicle always:

Keep right foot on brake pedal.


Firmly depress parking brake pedal.


Shift the automatic transmission toP.


Slowly release brake pedal.


When parked on an incline, turn front
wheels towards the road curb.


483 Operation
Driving instructions
Hydroplaning
Depending on the depth of the water layer
on the road, hydroplaning may occur, even
at low speeds and with new tires. Reduce
vehicle speed, avoid track grooves in the
road and apply brakes cautiously in the
rain.
Tire traction
The safe speed on a wet, snow covered or
icy road is always lower than on a dry road.
You should pay particular attention to the
condition of the road whenever the outside
temperatures are close to the freezing
point.Mercedes-Benz recommends winter tires
(
page 530) with a minimum tread depth
of approximately
1/6in (4 mm) on all four
wheels for the winter season to ensure
normal balanced handling characteristics.
On packed snow, they can reduce your
stopping distance compared to summer
tires.
Stopping distance, however, is still consid-
erably greater than when the road is not
covered with snow or ice. Exercise appro-
priate caution.
Warning!
G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle. You
may lose control of the vehicle. Continued
driving with a flat tire or driving at high
speed with a flat tire will cause excessive
heat build-up and possibly a fire.
Warning!
G
If ice has formed on the road, tire traction
will be substantially reduced. Under such
weather conditions, drive, steer and brake
with extreme caution.
!
Avoid spinning of a drive wheel. This may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited War-
ranty.

500 OperationTires and wheelsSee an authorized Mercedes-Benz Center
for information on tested and
recommended rims and tires for summer
and winter operation. They can also offer
advice concerning tire service and
purchase.
Important guidelines

Only use sets of tires and rims of the
same type and make.


Tires must be of the correct size for the
rim.


Break in new tires for approximately
60 miles (100 km) at moderate
speeds.


Regularly check the tires and rims for
damage. Dented or bent rims can
cause tire inflation pressure loss and
damage to the tire beads.


If vehicle is heavily loaded, check tire
inflation pressure and correct as
required.


Do not allow your tires to wear down
too far. Adhesion properties on wet
roads are sharply reduced at tread
depths under
1/8in (3 mm).


When replacing individual tires, you
should mount new tires on the front
wheels first (on vehicles with
same-sized wheels all around).
Warning!
G
Replace rims or tires with the same designa-
tion, manufacturer and type as shown on the
original part. See an authorized
Mercedes-Benz Center for further informa-
tion. If incorrectly sized rims and tires are
mounted:

The wheel brakes or suspension
components can be damaged.


The operating clearance of the wheels
and the tires may no longer be correct.
Warning!
G
Worn, old tires can cause accidents. If the
tire tread is badly worn, or if the tires have
sustained damage, replace them.
When replacing rims, only use Genuine
Mercedes-Benz wheel bolts specified for the
particular rim type. Failure to do so can
result in the bolts loosening and possibly an
accident.
Retreaded tires are not tested or recom-
mended by Mercedes-Benz, since previous
damage cannot always be recognized on re-
treads. The operating safety of the vehicle
cannot be assured when such tires are used.

512 OperationTires and wheelsThe TPMS only functions on wheels that
are equipped with the proper electronic
sensors. It monitors the tire inflation pres-
sure, as selected by the driver, in all four
tires. A warning is issued to alert you to a
decrease in pressure in one or more of the
tires.
Tire inflation pressure inquiries are made
using the multifunction display. The
present inflation pressures are displayed
only after a few minutes of travel time.
Switch on the ignition (
page 315).

Press( or& to select the menu
“Service”.

Press$ or% to select “Tire
pressure”.

Press#.
i
Possible differences between the readings
of a tire inflation pressure gauge of an air hose,
e.g. gas station equipment, and the vehicle’s
control system can occur. Usually the readings
issued by the control system are more precise.
i
The menu overview can be found on
(
page 243).
i
When the message “Tire pressures dis-
played after driving a few minutes” appears in
the display, the individual inflation pressure val-
ues are matched with the tires. The individual
values are displayed after a few minutes driving.Warning!
G
It is the driver’s responsibility to calibrate
the TPMS on the recommended cold infla-
tion pressure. Underinflated tires affect the
ability to steer or brake the vehicle. You
might lose control over the vehicle.
i
With a spare wheel without wheel sensor
mounted, the system may still indicate the tire
inflation pressure of the removed wheel for some
minutes. If this happens, keep in mind that the
indicated value where the spare wheel is mount-
ed does not reflect the actual spare tire inflation
pressure.Warning!
G
The TPMS does not indicate a warning for
wrongly selected inflation pressures. Always
adjust tire inflation pressure according to
the placard on the driver’s door B-pillar or, if
available, the supplemental tire pressure in-
formation on the inside of the fuel filler flap.
The TPMS is not able to issue a warning due
to a sudden dramatic loss of pressure (e.g.
tire blowout caused by a foreign object). In
this case bring the vehicle to a halt by care-
fully applying the brakes and avoiding
abrupt steering maneuvers.

516 OperationTires and wheels
Reactivating the Run Flat Indicator
The tire inflation pressure monitor must be
reactivated in the following situations:

If you have changed the tire inflation
pressure


If you have replaced the wheels or tires


If you have installed new wheels or
tires

Using the tire placard on the driver’s
door B-pillar (
page 503) or, if avail-
able, the inside of the fuel filler flap
(
page 489), make sure the tire infla-
tion pressure of all four tires is correct.

Switch on the ignition (
page 315).

Press( or& to select the menu
“Service”.

Press$ or% to select “Tire
pressure”.

Press#.
The message
Run Flat Indicator
active
Reactivation possible: OK
appears in the multifunction display.

Press#.
The message
Tire pressure
now OK?
appears in the multifunction display.
Warning!
G
The Run Flat Indicator does not provide a
warning for wrongly selected tire inflation
pressures. Always adjust tire inflation pres-
sure according to the placard on the driver’s
door B-pillar or fuel filler flap.
The Run Flat Indicator does not replace reg-
ular checks of the tire inflation pressures
since a gradual pressure loss in all four tires
cannot be detected by the Run Flat
Indicator.
The Run Flat Indicator is not able to issue a
warning due to a sudden dramatic loss of
tire inflation pressure (e.g. tire blowout
caused by a foreign object). In this case
bring the vehicle to a halt by carefully apply-
ing the brakes and avoiding abrupt steering
maneuvers.
Warning!
G
The Run Flat Indicator can only warn you in
a reliable manner if you have set the correct
tire inflation pressures for each tire.
If an incorrect tire inflation pressure was
set, the system will monitor the pressure ac-
cording to the incorrect value.
i
The menu overview can be found on
(
page 243).