2003 MERCEDES-BENZ SL55AMG brake sensor

171 Controls in detail
Driving systems
Distronic*
When activated, the Distronic adaptive
cruise control system increases the driving
convenience afforded by the cruise control
during travel on expressways and other
major roads.

If the Distronic distance sensor detects
a slower moving vehicle directly ahead,
your vehicle speed will be reduced so
that you follow that vehicle at a preset
distance.


If there is no vehicle directly ahead of
you, Distronic will function in the same
way as cruise control (
page 168).
Warning!
G
Distronic adaptive cruise control is no sub-
stitute for active driving involvement. It does
not react to stationary objects, nor recog-
nize or predict the curvature and lane layout
or the movement of vehicles ahead. Distron-
ic can only apply a maximum of 20% of the
vehicle’s braking power.
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.Warning!
G
Distronic is a convenience system, its speed
adjustment reduction capability is intended
to make cruise control more effective and
usable when traffic speeds vary. It is not
however, intended to, nor does it, replace
the need for extreme care. The responsibili-
ty for the vehicle speed and the distance to
the vehicle ahead, including most impor-
tantly brake operation to assure safe stop-
ping distance, always rests with the driver.
Distronic cannot take street and traffic con-
ditions into account.
Warning!
G
Distronic requires familiarity with its opera-
tional characteristics. We strongly recom-
mend that you review the following
information carefully before operating the
system.iFor operation in the USA only: This de-
vice complies with Part 15 of the
FCC Rules. Operation is subject to the
following two conditions:

This device may not cause harmful
interference, and


this device must accept any inter-
ference received, including interfer-
ence that may cause undesired
operation.
Any unauthorized modification to this
device could void the user’s authority
to operate the equipment.

181 Controls in detail
Driving systems
The most likely cause for a malfunctioning
system is a dirty sensor (located behind
the hood grill), especially at times of snow
and ice or heavy rain. In such a case, Dis-
tronic will switch off, and the message DISTRONIC - CLEAR SENSOR!
appears in
the multifunction display.
For cleaning and care of the Distronic sen-
sor, see “Cleaning the Distronic* system
sensor cover” (
page 246).Turns and bends
In turns or bends, Distronic 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.
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.
Distronic regulates only the distance be-
tween your vehicle and those directly ahead
of it, but does not register stationary objects
in the road, e.g.:


a stopped vehicle in a traffic jam


a disabled vehicle


an oncoming vehicle
The driver must always be on the alert, ob-
serve all traffic and intercede as required by
steering or braking the vehicle.Warning!
G
Distronic should not be used in snowy or icy
road conditions.

186 Controls in detailDriving systemsParktronic system*
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
and release the parking brake. The Park-
tronic system deactivates at speeds over
11 mph (18 km/h). At lower speeds the
Parktronic system turns on again.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
can be affected by dirty sensors, especially
at times of snow and ice. See Cleaning the
Parktronic system sensors (
page 246).
Interference caused by other ultrasonic sig-
nals (e.g. working jackhammers or the air
brakes of trucks) can cause the system to
send erratic indications, and should be tak-
en into consideration.
Warning!
G
Make sure that no persons or animals are in
the area in which you are maneuvering. Oth-
erwise you run the risk of causing injury.

187 Controls in detail
Driving systems
Range 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.
Front sensorsRear sensors Minimum distance
If you encounter an obstacle in this range,
all the warning lamps light up and you hear
a warning signal. If the obstacle is closer
than the minimum distance, the actual dis-
tance may no longer 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 located above the center air
vents in the dashboard. The warning indi-
cator for the rear area is integrated in the
rear trim.Center
approx. 40 in (100 cm)
Corners
approx. 48 in (120 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 Park-
tronic system will not detect such ob-
jects at close range and damage to
your vehicle or the object may result.
Ultrasonic signals from outside sourc-
es (e.g. truck air brakes or jackham-
mers) may impair the operation of the
Parktronic system.
Center
approx. 8 in (20 cm)
Corners
approx. 6 in (15 cm)

236 OperationTires and wheelsRegularly check your tire pressure at inter-
vals of no more than 14 days.
Tire pressure changes by approximately
1.5 psi (0.1 bar) per 18°F (10°C) of air
temperature change. Keep this in mind
when checking tire pressure where the
temperature is different from the outside
temperature.
The tire temperature and with it the tire
pressure is increased also while driving,
depending on the driving speed and the
tire load.
Checking tire pressure electronically*
The tire inflation pressure monitor only
functions on wheels that are equipped with
the proper electronic sensors. It monitors
the tire inflation pressure, as selected by
the driver, in all four tires. A warning is is-
sued to alert you to a decrease in pressure
in one or more of the tires.Tire pressure inquiries are made using the
multifunction display (
page 110). The
present inflation pressures are displayed
only after a few minutes travel time.
You can select the unit of measure used for
the tire inflation pressure by changing the
setting in the control system (
page 129).

Switch on ignition.

Press
k
button until the current in-
flation pressures for each tire appear in
the tachometer display field.
iPossible differences between the read-
ings of a tire pressure gauge of an air
hose, e.g. gas station equipment, and
the vehicle’s control system can occur.
The readings issued by the control sys-
tem are more precise.
Warning!
G
The tire inflation pressure monitor does not
indicate a warning for wrongly selected in-
flation pressures. Always adjust tire inflation
pressure according to the label on the fuel
filler flap.
The tire inflation pressure monitor is not
able to issue a warning due to a sudden loss
of pressure (e.g. tire puncture caused by a
foreign object). In the event of a sudden loss
of pressure, bring the vehicle to a halt by
carefully applying the brakes and avoiding
abrupt steering maneuvers.

251 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
-
The yellow ABS malfunction indi-
cator lamp comes on while driv-
ing.
The ABS has detected a malfunction and has
switched off. The BAS and ESP are also
switched off (see messages in display).
The SBC brake system is still functioning nor-
mally but without ABS available.
If the ABS control unit is malfunctioning, oth-
er systems such as Parktronic*, Distronic*,
or the automatic transmission may also be
malfunctioning.

Continue driving with added caution.
Wheels may lock during hard braking,
reducing steering capability.

Have the system checked at an autho-
rized Mercedes-Benz Center as soon
as possible.
Failure to follow these instructions in-
creases the risk of an accident.

Read and observe messages in the
display (
page 257).
E
The red DTR indicator lamp lights
up while driving.
You are too close to the vehicle in front of you
to maintain selected speed.

Apply the brakes immediately to in-
crease the following distance.
E
The red DTR indicator lamp
comes on while driving and you
hear a warning sound.


You are gaining too rapidly on the vehicle
ahead of you.


The distance warning system has recog-
nized a stationary obstacle on your prob-
able line of travel.

Apply the brakes immediately.

Carefully observe the traffic situation.
You may need to brake or maneuver
to avoid hitting an obstacle.
E
The white DTR indicator lamp
lights up while driving.
The Distronic* distance sensor has recog-
nized a vehicle in front of you.

282 Practical hintsWhat to do if …Left display
Right display
Possible cause
Possible solution
Tire pressure
control activated!
Pressure display after
driving several mins.
The tire pressure is being checked.
H
Reactivate
tire press. monit
.
The tire inflation pressure monitor* is de-
activated.

Activate the tire inflation pressure
monitor* (
page 237).
Tire press. monit.
currently inactive
The tire inflation pressure monitor* is un-
able to monitor the tire pressure due to:

the presence of several wheel sensors
in the vehicle


excessive wheel sensor temperatures


a nearby radio interference source


unrecognized wheel sensors mounted

Check the tire pressure at the next
service station.
Warning!
G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle.
You may lose control of the vehicle. Contin-
ued driving with a flat tire will cause exces-
sive heat build-up and possibly a fire.

283 Practical hints
What to do if …
Left display
Right display
Possible cause
Possible solution
H
Tire press. monit.
Visit workshop!
The tire inflation pressure monitor is
malfunctioning.
A wheel without proper sensor was
installed.

Have the tire inflation pressure monitor
checked by an authorized Mercedes-Benz
Center.

Change the wheel.
Tire pressure, RL
Caution
tire defect!
The left rear tire is rapidly deflating.

Carefully bring the vehicle to a halt, avoiding
abrupt steering and braking maneuvers.

Change the wheel (
page 312).
Tire pressure, RL
Check tires!
The left rear tire pressure is low.

Carefully bring the vehicle to a halt.

Check the tire pressure.

Change the wheel (
page 312).
Warning!
G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle. You
may lose control of the vehicle.
Continued driving with a flat tire will cause
excessive heat build-up and possibly a fire.