2008 MERCEDES-BENZ S550 4MATIC sensor

431 Controls in detail
Driving systems

if ESP® is switched off

if the hood is open

if the driver’s door is open and the driv-
er has not fastened his or her seat belt

if the radar sensors are switched off
(
page 282).
Switching on while driving
Tap DISTRONIC Plus lever up1 or
down2 until desired speed is set.
DISTRONIC Plus is switched on.
or
Pull DISTRONIC Plus lever briefly in di-
rection of arrow4 to call up speed
last set (
page 435).
DISTRONIC Plus is switched on.
Take your foot off the accelerator ped-
al.
Your vehicle adapts its speed to the ve-
hicle ahead, observing the set speed as
a maximum value.Switching on when approaching a sta-
tionary vehicle
If the vehicle in front of you is stationary,
you can only switch on DISTRONIC Plus if
your vehicle is also at a standstill.
Tap DISTRONIC Plus lever up1 or
down2 until desired speed is set.
DISTRONIC Plus is switched on.
or
Pull DISTRONIC Plus lever briefly in di-
rection of arrow4 to call up speed
last set (
page 435).
DISTRONIC Plus is switched on.
iUnder 20 mph, you can only switch on
DISTRONIC Plus if the vehicle ahead of you has
been detected and is shown on the multifunction
display. If you no longer see the vehicle in front
of you on the multifunction display and if it is no
longer detected because it has changed lanes,
for example, DISTRONIC Plus switches off and
you will hear a signal.
iIf you do not completely lift your foot off the
accelerator pedal, the message“DISTRONIC
PLUS override” appears on the multifunction dis-
play. The distance to a slower-driving vehicle will
not be set. You will drive at the speed you dictate
by pressing the accelerator pedal.
iIt is helpful to switch on the DISTRONIC Plus
display in the instrument cluster (
page 428)
since you can only switch on DISTRONIC Plus un-
der a speed of 20 mph when a vehicle has been
detected in front of you.
iYou can adjust the set speed using the
DISTRONIC Plus lever and the target distance
using the distance setting switch on the
DISTRONIC Plus lever (
page 436).

436 Controls in detail
Driving systems

the radar sensors are switched off
(
page 282)

the vehicle rolls backward
The segments in the multifunction display
go out, an acoustic signal sounds, and the
message “DISTRONIC PLUS Off” appears in
the multifunction display for approximately
5 seconds.
If the vehicle has been stopped by
DISTRONIC Plus and a malfunction occurs
in the system, the message “Brake immedi-
ately” will appear on the multifunction dis-
play. Step on the brake immediately to
prevent the vehicle from rolling.
DISTRONIC Plus is then switched off and
the message disappears.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.
Warning!G
DISTRONIC Plus switches off and releases
the brakes when the vehicle decelerates be-
low the minimum speed of 20 mph by oper-
ation of the system unless DISTRONIC Plus
detects a vehicle directly ahead of you. At
that time the driver must apply the brakes in
order to reduce vehicle 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).
iDepressing 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.

438 Controls in detail
Driving systems
The most likely cause for a malfunctioning
system is a dirty sensor (located behind
the hood grille), especially at times of snow
and ice or heavy rain. In such a case,
DISTRONIC Plus will switch off, and the
message:
“DISTRONIC PLUS
currently unavailable
See Oper. Manual”
appears in the multifunction display.
For cleaning and care of the
DISTRONIC Plus sensor, see “Cleaning the
DISTRONIC Plus*/ PRE-SAFE
® Brake*
system sensors (USA only)” (
page 589).Another cause might be that the radar sen-
sors have been manually switched off in
the instrument cluster control system.
Please verify that the radar sensors are
switched on (
page 282).Turns and bends
In turns or bends, DISTRONIC Plus may not
detect a moving vehicle in front, or it may
detect one too soon. This may cause your
vehicle to brake late or unexpectedly.
iIf the message:
“DISTRONIC PLUS
currently unavailable
See Oper. Manual”
disappears during driving and the last speed
stored flashes for approximately 5 seconds, the
dirt (e.g. slush) has dissolved; DISTRONIC Plus is
again available.

445 Controls in detail
Driving systems
The Parktronic system 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.
The Parktronic system is automatically ac-
tivated when you switch on the ignition, re-
lease the electronic 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.
The Parktronic system also deactivates
when you set the automatic transmission
to P or secure the vehicle in place with the
electronic 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*)Range of the sensors
!The operational function of the Parktronic
system can be affected by dirty sensors, espe-
cially at times of snow and ice.
Make sure that the area on the bumpers around
the sensors is free of dirt, ice and/or slush,
otherwise Parktronic may not function properly,
see “Cleaning the Parktronic* system sensors”
(
page 589).
iInterference 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.
iTo 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 589).

446 Controls in detail
Driving systems
Front 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.Warning indicators
Visual signals indicate to the driver the rel-
ative distance between the sensors and an
obstacle.
The warning indicator for the front area is
in the instrument cluster. The warning indi-
cator for the rear area is on the roof liner in
the rear.
1Left side of the vehicle
2Right side of the vehicle
3Indicator
Each warning indicator is divided into five
yellow and two red distance segments for
either side of the vehicle.
If yellow indicators 3 under the segments
are lit, Parktronic is ready to measure.
Centerapprox. 40 in (100 cm)
Cornersapprox. 24 in (60 cm)
Centerapprox. 48 in (120 cm)
Cornersapprox. 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.
Centerapprox. 8 in (20 cm)
Cornersapprox. 6 in (15 cm)

448 Controls in detail
Driving systems
Switching off the Parktronic sys-
tem: Press button 1.
Indicator lamp 2 comes on.
Switching on the Parktronic system:
Press button 1 again.
Indicator lamp 2 goes out.
Parktronic system malfunction
If only the red distance segments illumi-
nate and an acoustic warning sounds,
there is a malfunction in the Parktronic
system. The Parktronic system will auto-
matically switch off after 20 seconds and
the indicator lamp in the Parktronic switch
comes on.
Have the Parktronic system checked
by an authorized Mercedes-Benz Cen-
ter as soon as possible.
If only the red distance segments illumi-
nate and no acoustic warning sounds, the
Parktronic system sensors are dirty or
there is an interference from other radio or
ultrasonic signals. The Parktronic system
will automatically switch off after 20 sec-
onds and the indicator lamp in the Park-
tronic switch comes on.
Switch off the ignition (page 344).
Clean the Parktronic system sensors
(
page 589).
Switch on the ignition.
or
Check the Parktronic system operation
at another location to rule out interfer-
ence from outside radio or ultrasonic
signals.
Park Assist*
iThe Parktronic system is automatically
switched on when the ignition is switched on
(
page 344).
Warning!G
Park Assist 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 remains with the driver.
Warning!G
Make sure no persons or animals are in the
area in which you are maneuvering. You
could otherwise injure them.
!Special attention must be paid to objects
with smooth surfaces or low silhouettes (e.g.
trailer couplings, painted posts, elevated cross-
bars or road curbs). Such objects may not be de-
tected by the system and can damage the
vehicle.

449 Controls in detail
Driving systems
Park Assist is an electronic parking aid
with radar sensors that helps you while
parking.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* (page 424)

Park Assist

PRE-SAFE® Brake* (page 76)
It visually and audibly indicates the relative
distance between the vehicle and an ob-
stacle.
Park Assist is automatically activated
when the engine is running and the trans-
mission is in position D, R or N.
The Park Assist system deactivates at
speeds over approximately 11 mph. At
lower speeds the Parktronic system turns
on again.
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.
!The operational function of the Park Assist
system can be affected by dirty sensors, espe-
cially at times of snow and ice.
Make sure that the area on the bumpers around
the sensors is free of dirt, ice and/or slush,
otherwise Park Assist may not function properly,
see “Cleaning the Park Assist* system sensors
(USA only)” (
page 590).
!High-frequency sources such as toll sta-
tions, speed measuring systems, etc. can cause
the Park Assist system to malfunction. You can
switch off the Park Assist using the Park Assist
button (
page 452) or switch off the radar sen-
sors (
page 282) to prevent possible malfunc-
tion.

450 Controls in detail
Driving systems
Park Assist is also switched off when you
set the automatic transmission to P or
switch off the engine.
While the transmission is in neutral
positionN, Park Assist is switched off if
you secure the vehicle in place with the
electronic parking brake.
The Park Assist system monitors the sur-
roundings of your vehicle with four sensors
in the front bumper and two sensors in the
rear bumper.Range of the sensors
The sensors of the Park Assist system are
integrated in the front and rear bumpers.
Make sure that the bumpers are clear of
dirt, ice and slush in the area of the sen-
sors, as otherwise, Park Assist may not
function properly, see “Cleaning the Park
Assist* system sensors (USA only)”
(
page 590).