2008 MERCEDES-BENZ CL-Class brakes

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).
i
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.

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.
i
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.

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).
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.
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 600).

465 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
3Readiness indicators
Each warning indicator is divided into five
yellow and two red distance segments for
either side of the vehicle.
If yellow readiness indicators 3 under the
distance segments are lit, Parktronic is
ready to measure.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
result.
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)

540 OperationDriving instructionsBrakes
To 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 or BAS Plus*) (
page 67).
Brake pad wear or a leak in the system may
be the reason for low brake fluid level in
the reservoir.
The brake fluid level in the reservoir may
be too low if the red brake warning lamp in
the instrument cluster comes on while the
engine is running and an acoustic warning
sounds (
page 611). Observe additional
messages in the multifunction display that
may appear (page 622).
Have the brake system inspected
immediately. Contact an authorized
Mercedes-Benz Center.
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
effect. 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
accident.
!
Because the ESP
® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO start/stop button* in position0
or1) when


the electronic parking brake is being tested
on a brake test dynamometer


the vehicle is being towed with the
front/rear axle raised
Active braking action through the ESP
® may oth-
erwise seriously damage the brake system.
Warning!
G
Make sure not to endanger any other road
users when carrying out these braking ma-
neuvers.

541 Operation
Driving instructions
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.
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.High-performance brake system
(CL 63 AMG and CL 65 AMG only)
The high-performance brake system is de-
signed to operate under the extremely high
operating demands required to accommo-
date the performance capabilities of the
vehicle. The brakes may produce a squeak-
ing-type noise depending on the


vehicle speed


brake force applied


ambient conditions, e.g. temperature
and humidity
As with any brake system, the wear of indi-
vidual brake system components such as
brake pads or disks strongly depends on
your driving style and the conditions under
which you operate the vehicle. Thus, a driv-
ing style calling for high demand braking
will cause your vehicle’s brakes to wear
more quickly.
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 Lim-
ited Warranty.

542 OperationDriving instructions
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.
Parking
Warning!
G
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 mes-
sages in the multifunction display. Especial-
ly for high performance driving, it is
important to maintain and have the brake
system checked regularly.
!
When driving off on a slippery surface, do
not allow a drive wheel to spin for an extended
period with the ESP
® switched off. Doing so 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 brakes reduces engine
performance and causes premature brake wear
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, or
damage to the vehicle drivetrain, as a result
of inadvertent vehicle movement, before
turning off the engine and leaving the vehi-
cle always:

Keep right foot on brake pedal.


Engage electronic parking brake.


Shift the automatic transmission toP.


Slowly release brake pedal.


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