2008 MERCEDES-BENZ CL550 brake

451 Controls in detail
Driving systems
Switching on when approaching a
stationary 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 455).
DISTRONIC Plus is switched on.Starting off
When the vehicle in front of you starts off:

Remove your foot from the brake
pedal.

Pull DISTRONIC Plus lever briefly in di-
rection of arrow4.
or

Briefly step on the accelerator pedal.
Your vehicle starts off and adapts its speed
to the vehicle in front of you.Driving
If no vehicle is driving ahead of you,
DISTRONIC Plus functions like the cruise
control (
page 437).
When DISTRONIC Plus detects that the ve-
hicle in front of you is driving more slowly,
it brakes the vehicle in order to keep the
distance specified by you.
When DISTRONIC Plus detects that the ve-
hicle in front of you is driving faster, the ve-
hicle accelerates up to the set speed.
i
It is helpful to switch on the DISTRONIC Plus
display in the instrument cluster (
page 448)
since you can only switch on DISTRONIC Plus un-
d e r a s p e e d o f 2 0 m p h ( 3 0 k m / h ) w h e n a v e h i c l e
has been detected in front of you.
i
You 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 457).
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If DISTRONIC Plus is switched off,
PRE-SAFE
® Brake* (
page 75) will warn of an
impending collision if this function has been
activated with the instrument cluster control
system (
page 298).
Warning!
G
When you step on the brake pedal, you
switch off DISTRONIC Plus except when the
vehicle is at a standstill. DISTRONIC Plus will
no longer brake your vehicle. You are always
responsible for maintaining a distance from
other vehicles, observing road speeds and
braking well in advance.

452 Controls in detailDriving systemsStoppingWhen DISTRONIC Plus detects that the ve-
hicle in front of you is stopping, the vehicle
brakes until it also stops.
Once DISTRONIC Plus has stopped your
vehicle and it is at a standstill, it remains
stationary; the brake pedal does not need
to be depressed.Warning!
G
DISTRONIC Plus’s braking effect is canceled
and the vehicle can start to roll if

DISTRONIC Plus is switched off using
the DISTRONIC Plus lever


you accelerate


the system or the power supply is mal-
functioning, e.g. due to battery failure


the electrical components in the engine
compartment or the fuses have been
manipulated


the battery is disconnected
Warning!
G
Never get out of the vehicle while
DISTRONIC Plus is switched on!
DISTRONIC Plus must never be operated or
switched off by passengers or from outside
the vehicle.
DISTRONIC Plus is not a substitute for the
electronic parking brake and may not be
used for parking.
When you get out of the vehicle or switch off
the engine, deactivate DISTRONIC Plus and
secure the vehicle from rolling away by en-
gaging the electronic parking brake.
i
After a short while, your vehicle is secured in
place by the electronic parking brake so that the
operating brake can be relieved of load.
i
Depending on the following distance set us-
ing the distance setting switch on the DISTRON-
IC Plus lever, your vehicle will stop
approximately 13.1 ft away from the vehicle in
front of you.

454 Controls in detailDriving systemsAdjustment in 5 mph
(Canada: 10 km/h) increments

Briefly lift the DISTRONIC Plus lever up
past the resistance point in direction of
arrow1 (
page 449).

Release the DISTRONIC Plus lever.
The vehicle speed increases in incre-
ments of 5 mph (Canada: 10 km/h).Setting a lower speed
You can reduce the speed in two ways.
Warning!
G
You can increase the vehicle speed in 5 mph
(Canada: 10 km/h) increments. When using
this feature, keep in mind that it may take a
brief moment until the vehicle has reached
the set speed.
Increase the vehicle speed to a value that
the prevailing road conditions permit. Other-
wise, sudden and unexpected acceleration
of the vehicle could cause an accident
and/or serious injury to you and others.
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The set speed value is increased in 5 mph
(Canada: 10 km/h) increments each time you
lift the DISTRONIC Plus lever up past the resis-
tance point.
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The 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 decrease the set speed, keep in mind
that it may take a brief moment until the ve-
hicle has reached the set speed.
Decelerate the set speed to a value that the
prevailing road conditions and legal speed
limits permit. Otherwise, sudden and unex-
pected deceleration of the vehicle could
cause an accident and/or serious injury to
you and others.i
When you use the DISTRONIC Plus lever to
decelerate, the brake system will automatically
brake the vehicle if the engine’s braking power
does not brake the vehicle sufficiently.

456 Controls in detailDriving systemsDeactivating DISTRONIC Plus
There are several ways to deactivate the
DISTRONIC Plus system:
Briefly tip the DISTRONIC Plus lever in
the direction of arrow3 (
page 449).
or

Step on the brake pedal.
DISTRONIC Plus will be deactivated.
The last speed set will be stored into
memory.DISTRONIC Plus deactivates automatically
when:


the vehicle is secured with the elec-
tronic parking brake


the vehicle speed is below 20 mph
(30 km/h) and no preceding vehicle is
detected


the ESP
® is in operation or switched off
with the ESP
® switch (
page 72)


you set the automatic transmission to
park positionP, reverse gearR, or neu-
ral positionN while driving


the radar sensors are switched off
(page 302)


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.
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The last stored set speed is deleted when
the engine is turned off.
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.

458 Controls in detailDriving systemsIncreasing distance
Increasing the distance setting causes
DISTRONIC Plus to maintain a greater fol-
lowing distance to the preceding vehicle.
Move distance setting switch 1 in di-
rection 2.
Decreasing distance
Decreasing the distance setting causes
DISTRONIC Plus to maintain a shorter fol-
lowing distance to the preceding vehicle.

Move distance setting switch 1 in di-
rection 3.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. Braking
will deactivate the DISTRONIC Plus sys-
tem.
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:
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
your set distance).
This means that:

Your vehicle can pass another vehicle
after you change lanes.


While in a sharp turn or if the vehicle in
front is in a sharp turn, DISTRONIC Plus
could lose sight of a vehicle traveling in
front of it, then your vehicle could accel-
erate to the previously selected speed.
DISTRONIC Plus regulates only the distance
between your vehicle and those directly
ahead of it. It may not register stationary ob-
jects in the road, e.g.:

a stopped vehicle in a traffic jam


a disabled vehicle


an oncoming vehicle
The driver must always be alert, observe all
traffic and intercede as required by means
of steering or braking the vehicle.
Warning!
G
DISTRONIC Plus should not be used in
snowy or icy road conditions.

459 Controls in detail
Driving systems
“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* sys-
tem sensors (USA only)”(
page 599).
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 302).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.Offset driving
A vehicle traveling in your lane but offset
from your direct line of travel may not be
detected by DISTRONIC Plus. There will be
insufficient distance to the vehicle ahead.
i
If 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
available again.

460 Controls in detailDriving systemsLane changing
DISTRONIC Plus has not yet detected the
vehicle changing lanes. There will be insuf-
ficient distance to the lane-changing
vehicle.Narrow vehicles
Because of their narrow profile, the vehi-
cles traveling near the outer edge of the
lane have not yet been detected by
DISTRONIC Plus. There will be insufficient
distance to the vehicles ahead.Obstacles and stationary vehicles
DISTRONIC Plus does not brake for obsta-
cles or stationary vehicles. If, for example,
the vehicle detected in front of you chang-
es lanes to bypass an obstacle or station-
ary vehicle in front of it, DISTRONIC Plus
will not brake for the obstacle or stationary
vehicle.

464 Controls in detailDriving systemsThe 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 drive positionD, re-
verse gearR or neutral positionN.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 park positionP 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 the Parktronic system may not
function properly, see “Cleaning the Parktronic*
system sensors” (
page 600).
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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.
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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 600).