2005 MERCEDES-BENZ SL55AMG brakes

211 Controls in detail
Driving systems
1Red DTR warning lamp E
Warning!
G
An intermittent warning sounds and the
DTR warning lamp (red) E in the speed-
ometer dial is illuminated if the Distronic
system calculates that the distance to the
vehicle ahead and your vehicle’s current
speed indicate that Distronic will not be ca-
pable of slowing the vehicle sufficiently to
maintain the preset following distance,
which creates a danger of a collision.
Immediately brake the vehicle to increase
the distance to the vehicle in front of you.
The warning sound is intended as a final cau-
tion that you have not interceded with your
own braking inputs to avoid a potentially
dangerous situation. Do not wait for the op-
eration of the warning signal to intercede
with your own braking, as that will result in
potentially dangerous emergency braking
which will not always result in an impact be-
ing avoided.
Tailgating increases the risk of an accident.
Warning!
G
The Distronic brakes your vehicle with a
maximum of 6.5 ft/s
2 (2 m/s
2). This corre-
sponds to about 20% of the maximum decel-
eration ability of your vehicle.
Distronic brakes the vehicle in an effort to
restore the preset distance or to maintain
the speed.

214 Controls in detailDriving systemsSetting the current speed
Accelerate or decelerate to the desired
speed.

Briefly lift or depress the cruise control
lever.
The current speed is set.

Remove your foot from the accelerator
pedal.Setting a higher speed

Briefly tip the cruise control in direction
of arrow1 (
page 213) to increase
the vehicle speed in increments of
5 mph (Canada: 10 km/h).
The new speed is set.Setting a lower speed

Briefly tip the cruise control in direction
of arrow2 (
page 213) to decrease
the vehicle speed in increments of
5 mph (Canada: 10 km/h).
The new speed is set.
Fine adjustment in 1 mph
(Canada: 1 km/h) increments
Faster

Briefly tip the cruise control lever in
direction of arrow4 (
page 213).
iIf you do not take your foot off of the
accelerator completely, the following
message will appear in the speedome-
ter display field:DTR override
.
The distance to slower moving vehicles
in front of you will not be set. Your ve-
hicle speed will then be determined
only by the accelerator pedal position.
iDepressing the accelerator pedal does
not deactivate Distronic. After brief ac-
celeration (e.g. for passing), the cruise
control will resume the last speed set.
iWhen you use the cruise control lever
to decelerate, the brakes will be ap-
plied to support deceleration.
In addition, the transmission will auto-
matically downshift on long downhill
grades.

215 Controls in detail
Driving systems
Setting to last stored speed (“Resume”
function)
Briefly tip the cruise control lever in
direction of arrow4 (
page 213).
Distronic is set to the last stored
speed.

Remove your foot from the accelerator
pedal.Deactivating Distronic
There are several ways to deactivate the
Distronic system:

Briefly tip the cruise control lever in
direction of arrow3 (
page 213).
or

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


you set the parking brake


you drive slower than 25 mph
(40 km/h)


the ESP is active (
page 82) or you de-
activate the ESP


You move the gear selector lever into
positionN.
A signal will sound. The
DTR off
mes-
sage appears in the speedometer dis-
play for approximately five seconds.
Warning!
G
The speed stored in memory should only be
set again if prevailing road conditions per-
mit. Possible acceleration or deceleration
differences arising from returning to the pre-
set speed could endanger yourself and oth-
ers.
iThe last stored speed is deleted when
you turn off the engine.
Warning!
G
Distronic switches off and releases the
brakes when the vehicle decelerates below
the minimum speed of 25 mph (40 km / h)
by operation of the system. At that time the
driver must apply the brakes in order to re-
duce vehicle speed further or bring it to a
stop.

217 Controls in detail
Driving systems
When pressing the brake pedal, the warn-
ing sound ceases. The warning sound will
also cease, when the distance to the vehi-
cle ahead is sufficient again without apply-
ing the brakes. In this case, the distance
warning lamp will also go out.
Activating

Press switch1.
The indicator lamp on the switch
comes on. A loudspeaker symbol ap-
pears in the speedometer display
(page 212).
Deactivating

Press switch1 once more.
The indicator lamp on the switch goes
out. No loudspeaker symbol appears in
the speedometer display.Driving with Distronic
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. This will
deactivate the Distronic system.
Warning!
G
If the DTR warning lamp (red) E in the
speedometer dial comes on while driving
and/or an intermittent warning sounds, im-
mediate attention on the part of the driver is
required.
As required by the traffic situation, apply the
brakes and navigate around a possible ob-
stacle. However, do not drive by relying on
the distance warning function, as this will re-
sult in an emergency braking application.
Especially depending on road surface condi-
tions and driver reaction, this will not always
enable you to avoid a collision.
iComplex driving situations are not al-
ways fully recognized by Distronic. This
could result in wrong or missing dis-
tance warnings.
Warning!
G
Distronic works to maintain the speed se-
lected by the driver unless a moving obsta-
cle proceeding directly ahead of it in the
same travel direction is detected (e.g. fol-
lowing another vehicle ahead of you at a dis-
tance set by Distronic). 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 could
lose sight of a vehicle traveling in front
of it. Your vehicle could then accelerate
to the previously selected speed.


223 Controls in detail
Driving systems
Parktronic* (Parking assist)
The Parktronic system is an electronic aid
designed to assist the driver during park-
ing maneuvers. It visually and audibly indi-
cates the relative distance between the
vehicle and an obstacle.
The Parktronic system is automatically ac-
tivated when you switch on the ignition, re-
lease the parking brake, or place the gear
selector lever in Position D, R, or N. The
Parktronic system deactivates at speeds
above 11 mph (18 km/h). At lower speeds
the Parktronic system turns on again.
The Parktronic system also deactivates
when you place the gear selector lever in
Position P or depress the brake pedal.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 bumperWarning!
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 318).
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.
Warning!
G
Make sure no persons or animals are in the
area in which you are maneuvering. Other-
wise you run the risk of causing injury.

224 Controls in detailDriving systemsRange of the sensors
To function properly, the sensors must be
free of dirt, ice snow and slush. Clean the
sensors regularly, being careful not to
scratch or damage the sensors, see
“Cleaning the Parktronic system* sensors”
(page 318).
Front sensors
Rear sensors
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
attention to objects located above or
below the height of the sensors (e.g.
planters or trailer hitches).
The Parktronic system will not detect
such objects at close range and dam-
age to your vehicle or the object may
result.
Ultrasonic signals from outside sourc-
es (e.g. truck air brakes, car wash, or
jackhammers) may impair the opera-
tion of the Parktronic system.

256 OperationDriving instructionsPower assistance
Brakes
Warning!
G
The brake system requires electrical energy
for operation.
A malfunction in the vehicle’s power supply
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. In such a case, the
red brake warning lamp (
page 326) and
warning messages (
page 335) in the in-
strument cluster come on while driving. To
brake, the driver must then apply signifi-
cantly greater brake pedal pressure and de-
press the pedal much further to obtain the
expected braking effect. If necessary, apply
full pressure to the brake pedal. Brakes are
only applied to the front wheels. Stopping
distance is increased! If there is a malfunc-
tion in the SBC brake system, we recom-
mend that the vehicle be transported with
all wheels off the ground using flatbed or ap-
propriate wheel lift/dolly equipment.
A tow bar must be used if circumstances do
not permit the use of the recommended
towing methods and the vehicle requires
towing with all four wheels on the ground.
Towing the vehicle with all four wheels on
the ground is only permissible for distances
up to 30 miles (50 km) and at a speed not to
exceed 30 mph (50 km/h). For more infor-
mation, see “Towing the vehicle”
(page 408).
With the engine not running, there is no
power assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the ve-
hicle.
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.

257 Operation
Driving instructions
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.
If the parking brake is released and the
brake warning lamp in the instrument clus-
ter stays on, there is a malfunction in the
SBC brake system (
page 85) or 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.
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 rec-
ommended by Mercedes-Benz.After hard braking, it is advisable to drive
on for some time, rather than immediately
parking, so the air stream will cool down
the brakes faster.
!Be very careful not to endanger other
road users when you apply the brakes.
Refer to the description of the Brake
Assist System (BAS) (
page 81).
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.
Be certain to read and observe the warning
notices on brake pad replacement
(page 86).
!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 pre-
vent overheating of the brakes and re-
duces brake pad wear.