MERCEDES-BENZ S550 4MATIC 2008 W221 Owner's Manual

420 Controls in detail
Driving systems
1Setting current or higher speed
Adjustment in 1 mph increments (to re-
sistance point) or 5 mph increments
(past resistance point)
(Canada: 1 km/h or 10 km/h)
2Setting current or lower speed
Adjustment in 1 mph increments (to re-
sistance point) or 5 mph increments
(past resistance point)
(Canada: 1 km/h or 10 km/h)
3Cancel cruise control
4Resume to last set speedActivating cruise control
You can activate the cruise control if the
vehicle speed is above 20 mph (30 km/h).
In the following cases you cannot activate
the cruise control:

when you brake

the vehicle is secured with the elec-
tronic parking brake

when the automatic transmission is set
to positionP, R, or N

when ESP® is switched off
Setting current speed
Accelerate or decelerate to the desired
speed.
Briefly lift the cruise control lever in
direction of arrow1 or depress in
direction of arrow2.
The current speed is set.
Warning!G
The cruise control brakes automatically so
that the set speed is not exceeded. The
brake pedal depresses when the cruise con-
trol engages the brakes.
Keep driver’s foot area clear at all times, in-
cluding the area under the brake pedal. Ob-
jects stored in this area may impair pedal
movement which could interfere with the
braking ability of the cruise control system.
Do not place your foot under the brake pedal
– your foot could become caught.
Keep in mind that the cruise control is a con-
venience system designed to assist the driv-
er during vehicle operation. The driver is and
must always remain responsible for the ve-
hicle’s speed and for safe brake operation.
iThe vehicle speed displayed in the speedom-
eter can briefly vary from the speed setting for
the cruise control system.

421 Controls in detail
Driving systems
Remove your foot from the accelerator
pedal.
The cruise control is activated.

The last set speed appears in the
multifunction display for approxi-
mately 5 seconds.

The corresponding speedometer
segments from the selected speed
to the vehicle maximum speed in
the multifunction display are illumi-
nated.

The set speed is shown by a triangle
in the speedometer.Canceling cruise control
There are several ways to cancel the cruise
control:
Step on the brake pedal.
The cruise control is canceled. The last
speed set is stored for later use.
or
Briefly push the cruise control lever in
direction of arrow3.
The cruise control is canceled. The last
speed set is stored for later use.
iOn uphill grades, the cruise control may not
be able to maintain the set speed. Once the
grade eases, the set speed will be resumed.
On downhill grades, the cruise control maintains
the set speed by braking with the vehicle’s brake
system. In addition, on longer downhill grades
the automatic transmission will downshift auto-
matically.
iThe last stored set speed is deleted when
the engine is turned off.
iThe cruise control switches off automatical-
ly when

you step on the brake pedal

the vehicle is secured with the electronic
parking brake
In this case the segments in the multifunc-
tion display go out and no warning sounds.

the vehicle speed is below 20 mph
(30 km/h)

the ESP® is in operation or switched off with
the ESP® switch (page 73)

you set the automatic transmission toN
while driving
The segments in the multifunction display go out,
An acoustic warning sounds and the message
“Cruise control off” appears in the multifunction
display for approximately 5 seconds.
!Setting the automatic transmission toN
while driving cancels the cruise control. Howev-
er, the automatic transmission should not be set
toN while driving except to coast when the vehi-
cle is in danger of skidding (e.g. on icy roads).

422 Controls in detail
Driving systems
Setting a higher speed
You can increase the set speed in two
ways.Adjustment in 1 mph (Canada: 1 km/h)
increments
Briefly lift the cruise control lever to the
resistance point in direction of
arrow1 (
page 420).
Release the cruise control lever.
The vehicle set speed increases in in-
crements 1 mph (Canada: 1 km/h).Adjustment in 5 mph
(Canada: 10 km/h) increments
Briefly lift the cruise control lever past
the resistance point in direction of
arrow1 (
page 420).
iDepressing the accelerator pedal does not
deactivate the cruise control. After brief acceler-
ation (e.g. for passing), the cruise control will re-
sume the last speed set.
Warning!G
If you increase the set speed, keep in mind
that it may take a brief moment until the ve-
hicle has made the necessary adjustments.
Increase the set speed to a value that the
prevailing road conditions and legal speed
limits permit. Otherwise, sudden and unex-
pected acceleration of the vehicle could
cause an accident and/or serious injury to
you and others.
iThe set speed value is increased in 1 mph
(Canada: 1 km/h) increments each time you lift
the cruise control lever up to the resistance
point.iThe set speed value is increased in 5 mph
(Canada: 10 km/h) increments each time you lift
the cruise control lever up past the resistance
point.

423 Controls in detail
Driving systems
Release the cruise control lever.
The vehicle set speed increases in in-
crements 5 mph (Canada: 10 km/h).
Setting a lower speed
You can reduce the set speed in two ways.Adjustment in 1 mph (Canada: 1 km/h)
increments
Briefly press the cruise control lever
down to the resistance point in direc-
tion of arrow2 (
page 420).
Release the cruise control lever.
The vehicle set speed decreases in in-
crements 1 mph (Canada: 1 km/h).
Adjustment in 5 mph
(Canada: 10 km/h) increments
Briefly press the cruise control lever
down past the resistance point in
direction of arrow2 (
page 420).
Release the cruise control lever.
The vehicle set speed decreases in in-
crements 5 mph (Canada: 10 km/h).
Setting to last stored speed
(“Resume” function)iThe new speed is set and the vehicle will ac-
celerate. Keep in mind that it may take a brief
moment until the vehicle has reached the set
speed.
Warning!G
If you increase the set speed, keep in mind
that it may take a brief moment until the ve-
hicle has made the necessary adjustments.
Increase the set speed to a value that the
prevailing road conditions and legal speed
limits permit. Otherwise, sudden and unex-
pected acceleration of the vehicle could
cause an accident and/or serious injury to
you and others.
iWhen you use the cruise control lever to de-
celerate, the brake system will automatically
brake the vehicle if the engine’s braking power
does not brake the vehicle sufficiently.
iThe set speed value is decreased in 1 mph
(Canada: 1 km/h) increments each time you
press the cruise control lever down to the resis-
tance point.
iThe set speed value is decreased in 5 mph
(Canada: 10 km/h) increments each time you
press the cruise control lever down past the re-
sistance point.
iThe new speed is set and the vehicle will de-
celerate. Keep in mind that it may take a brief
moment until the vehicle has reached the set
speed.
Warning!G
The set speed stored in memory should only
be set again if prevailing road conditions
permit. Possible acceleration or decelera-
tion differences arising from returning to the
preset speed could cause an accident
and/or serious injury to you and others.

424 Controls in detail
Driving systems
Briefly pull the cruise control lever in
the direction of arrow4 (
page 420).
The cruise control resumes to the last
set speed or if no speed is stored, it will
set and store the current speed.
Remove your foot from the accelerator
pedal.
The last set speed appears in the multi-
function display for approximately
5 seconds, and the corresponding
speedometer segments from the se-
lected speed to the vehicle maximum
speed are illuminated.
DISTRONIC Plus*
When activated, the DISTRONIC Plus adap-
tive cruise control system increases driv-
ing convenience afforded by the cruise
control during travel on expressways and
other major roadways.

If the DISTRONIC Plus distance sensor
detects a slower moving vehicle direct-
ly ahead, your vehicle speed will be re-
duced so that you follow that vehicle at
a preset distance.

If there is no vehicle directly ahead of
you, DISTRONIC Plus will function in
the same way as the cruise control
(
page 419).
DISTRONIC Plus functions within a speed
range of 0 to 120 mph.When travelling in Canada in a vehicle not
registered in Canada, you must switch off
the radar sensor system* (
page 282).
Canadian law does not permit the use of
the radar sensor system* (
page 282) for
vehicles from outside of Canada. When you
switch off the radar sensor system*, the
following functions are deactivated:

BAS Plus* (page 69)

DISTRONIC Plus

Park Assist* (page 448)

PRE-SAFE® Brake* (page 76)
iThe last stored set speed is deleted when
the engine is turned off.

425 Controls in detail
Driving systems
Warning!G
DISTRONIC Plus is a convenience system.
Its speed adjustment reduction capability is
intended to make the cruise control more ef-
fective and usable when traffic speeds vary.
It is not however, intended to, nor does it, re-
place the need for extreme care. The re-
sponsibility for the vehicle speed and the
distance to the vehicle ahead, including
most importantly brake operation to assure
safe stopping distance, always remains with
the driver.
DISTRONIC Plus cannot take street and traf-
fic conditions into account.
Complex driving situations are not always
fully recognized by DISTRONIC Plus. This
could result in wrong or missing distance
warnings.
Warning!G
DISTRONIC Plus adaptive cruise control is
no substitute for active driving involvement.
It does not react to pedestrians or stationary
objects, nor does it recognize or predict the
curvature and lane layout or the movement
of vehicles ahead. DISTRONIC Plus can only
apply a maximum of 40% of the vehicle’s
braking power.
DISTRONIC Plus may not detect narrow ve-
hicles 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 road, weather and traffic con-
ditions and to provide the steering, braking
and other driving inputs necessary to retain
control of the vehicle.
High-frequency sources such as toll sta-
tions, speed measuring systems etc. can
cause the DISTRONIC Plus system to tem-
porarily cease functioning.
Warning!G
DISTRONIC Plus requires familiarity with its
operational characteristics. We strongly rec-
ommend that you review the following infor-
mation carefully before operating the
system.
Warning!G
DISTRONIC Plus cannot take street and traf-
fic conditions into account. Only use
DISTRONIC Plus if the road, weather and
traffic conditions make it advisable to travel
at a steady speed.
Warning!G
Use of DISTRONIC Plus can be dangerous
on slippery roads. Rapid changes in tire trac-
tion can result in wheel spin and loss of con-
trol.


426 Controls in detail
Driving systems
DISTRONIC Plus does not act upon adverse
sight distance conditions. Do not use
DISTRONIC Plus during conditions of fog
and heavy rain, snow or sleet.
Warning!G
DISTRONIC Plus cannot take weather condi-
tions into account. Switch off
DISTRONIC Plus or do not turn it on if:

roads are slippery or covered with snow
or ice. The wheels could lose traction
while braking or accelerating, and the
vehicle could skid.

the sensor is dirty or visibility is
diminished due to snow, rain or fog. The
distance control could be impaired.
Always pay attention to traffic conditions
even while DISTRONIC Plus is switched on.
Otherwise, you may not be able to recognize
dangerous situations until it is too late and
could cause an accident resulting in person-
al or fatal injury to you or others.
Warning!G
The “Resume” function should only be oper-
ated if the driver is fully aware of the previ-
ously set speed and wishes to resume this
particular preset speed.
Warning!G
Close attention to road and traffic condi-
tions is imperative at all times, regardless of
whether or not DISTRONIC Plus is activated.
Use of DISTRONIC Plus can be dangerous
on winding roads as conditions do not allow
safe driving at a steady speed.
DISTRONIC Plus may not react to stationary
objects in the roadway (e.g. a stopped vehi-
cle in a traffic jam or a disabled vehicle).
DISTRONIC Plus will also not respond to on-
coming vehicles.
Switch off DISTRONIC Plus:

when changing from the left to the right
lane if vehicles are moving more slowly
in the left lane

when entering a turn lane or highway off
ramp

in complex driving situations, such as in
highway construction zones
In these situations, DISTRONIC Plus will
continue to maintain the set speed unless
deactivated.
DISTRONIC Plus is designed and intended
only to maintain a set speed and keep a set
distance from moving objects in front of it.
iDo not use DISTRONIC Plus if you are driv-
ing on a road with steep uphill or downhill slopes.
iDue to its radar-emitting nature DISTRONIC
Plus may have an appearance similar to a radar
detector to law enforcement officials. You may
want to refer to this section of your Operator’s
Manual when asked.


427 Controls in detail
Driving systems
DISTRONIC Plus displays in multifunc-
tion display
1Speed of the vehicle ahead
2Set speed
3Distance warning lamp
If DISTRONIC Plus is activated, the
marker2 indicates the set speed.
When DISTRONIC Plus detects a vehicle
driving ahead of you, the ring on the speed-
ometer dial lights up between the speed of
the vehicle ahead of you and set speed2.If DISTRONIC Plus calculates that there is
a danger of collision:

The distance warning lampl in the
instrument cluster comes on.

An intermittent warning sounds.
Immediately brake the vehicle to avoid
a collision.
Under no circumstances should the
driver await the intermittent warning
sound before braking. See the follow-
ing warning note.
The intermittent warning sound ceases
and the distance warning lampl
goes out when the necessary distance
to the vehicle ahead is again
established.
iUSA 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 de-
vice 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.
iCanada 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 re-
ceived, 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.
iThe vehicle speed displayed on the speed-
ometer can briefly vary from the speed setting
on the DISTRONIC Plus system.
Warning!G
An intermittent warning sounds and the dis-
tance warning lampl in the instrument
cluster is illuminated if the DISTRONIC Plus
system calculates that the distance to the


428 Controls in detail
Driving systems
Displaying the distance graphic
In the “Assistance” menu under “Distance
display” you see the current settings for
DISTRONIC Plus. The information shown in
the multifunction display depends on
whether DISTRONIC Plus is activated or
deactivated.
vehicle ahead and your vehicle’s current
speed indicate that DISTRONIC Plus will not
be capable of slowing the vehicle sufficiently
to maintain the preset following distance,
which creates a danger of a collision.
Immediately brake your vehicle to increase
the distance between your vehicle and the
vehicle in front of you. The warning sound is
intended as a final caution that you have not
interceded with your own braking inputs to
avoid a potentially dangerous situation. Do
not wait for the operation of the warning sig-
nal to intercede with your own braking, as
that will result in potentially dangerous
emergency braking which will not always re-
sult in an impact being avoided.
Tailgating increases the risk of an accident.
Warning!G
DISTRONIC Plus brakes your vehicle with a
maximum of 13 ft/s2. This corresponds to
about 40% of the maximum deceleration
ability of your vehicle.
You must also apply the brakes yourself to
avoid a collision. DISTRONIC Plus brakes
the vehicle in an effort to restore the preset
distance or to maintain the speed. The brake
pedal is automatically applied as this hap-
pens which results in the brake pedal mov-
ing.
Keep driver’s foot area clear at all times, in-
cluding the area under the brake pedal. Ob-
jects stored in this area may impair pedal
movement which could interfere with the
braking ability of the DISTRONIC Plus sys-
tem.
Do not place your foot under the brake pedal
– your foot could become caught.Warning!G
If you do not receive visual or acoustic warn-
ing signals during a critical traffic situation,
DISTRONIC Plus has either not recognized
the collision risk, has been deactivated or is
malfunctioning.
Remember, whether or not DISTRONIC Plus
is operating, it is ultimately always the driv-
ers responsibility to apply the brakes in or-
der to control the vehicle and avoid a
collision.
iFor activating or deactivating the
DISTRONIC Plus system, see “Activating
DISTRONIC Plus” (
page 430) or “Deactivating
DISTRONIC Plus” (
page 435).


429 Controls in detail
Driving systems
Press ( or & to select the
“Assistance” menu.
Press % or $ to select the
“Distance display” function.
Press #.
The DISTRONIC Plus distance graphic
appears and you will see one of the fol-
lowing displays on the multifunction
display.DISTRONIC Plus activated
When you turn DISTRONIC Plus on, you will
see the set speed in the multifunction dis-
play for about 5 seconds. You then see the
following display in the multifunction dis-
play.
1DISTRONIC Plus activated
2Your vehicle
3Preset distance threshold to vehicle
ahead
4Vehicle ahead, if detectedDISTRONIC Plus deactivated
If DISTRONIC Plus is deactivated, the stan-
dard display of DISTRONIC Plus appears in
the multifunction display.
1Vehicle ahead, if detected
2Actual distance to vehicle ahead
3Preset distance threshold to vehicle
ahead
4Your vehicle
iThe menu overview can be found on
(
page 266).