warning MERCEDES-BENZ S CLASS 2003 Owners Manual

199 Controls in detail
Driving systems
Distronic*
When activated, the Distronic adaptive
cruise control system increases 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 196).
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 traffic and road conditions
and to provide the steering, braking and oth-
er 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. However, it
is not intended to, nor does it, replace the
need for extreme care. The responsibility for
the vehicle speed and the distance to the ve-
hicle ahead, including most importantly
brake operation to assure safe stopping dis-
tance, 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.

200 Controls in detailDriving systemsWarning!
G
Distronic cannot take street and traffic con-
ditions into account. Only use Distronic if
the weather, road, and traffic conditions
make it advisable to travel at a steady
speed.Warning!
G
Use of Distronic can be dangerous on slip-
pery roads. Rapid changes in tire traction
can result in wheel spin and loss of control.
Distronic does not act upon adverse sight
distance conditions. Do not use Distronic
during conditions of fog and heavy rain,
snow or sleet.
Warning!
G
Close attention to road and traffic condi-
tions is imperative at all times, regardless of
whether or not Distronic is activated.
Use of Distronic can be dangerous on wind-
ing roads or in heavy traffic because condi-
tions do not allow safe driving at a steady
speed.
Distronic will not react to stationary objects
in the roadway (e.g. a stopped vehicle in a
traffic jam or a disabled vehicle). Distronic
will also not respond to oncoming vehicles.
Switch off Distronic:

when changing from the left to the right
lane if vehicles are moving more slowly
in the left lane


when entering a turn lane or highway off
ramp


in complex driving situations, such as in
highway construction zones
In these situations, Distronic will continue to
maintain the set speed unless deactivated.
Distronic is designed and intended only to
maintain a set speed and keep a set dis-
tance from moving objects in front of it.Warning!
G
The “Resume” function should only be oper-
ated if the driver is fully aware of the previ-
ously set speed and wishes to resume this
particular preset speed.

201 Controls in detail
Driving systems
Distronic displays in the speedometer
dialSet speedIf Distronic is activated, one or two seg-
ments light up around the set speed.
SegmentsIf Distronic detects a vehicle directly
ahead, the segments (representing the
difference) between the speed of the
vehicle ahead and the set speed light up.
If Distronic calculates that there is a dan-
ger of collision (
page 207):


The red Distronic warning lamp
l
in
the instrument cluster lights up.


An intermittent warning sounds.

Immediately brake the vehicle to avoid
a collision.Under no circumstances should the
driver await the intermittent warning
sound before braking.
The intermittent warning sound ceases
and the red Distronic warning
lamp
l
goes out when the neces-
sary distance to the vehicle ahead is
again established.
iThe vehicle speed displayed on the
speedometer can briefly vary from the
speed setting on the Distronic system.

202 Controls in detailDriving systems
Distronic menu in the control system
In the Distronic menu you see the current
settings for Distronic. What appears in the
display depends on whether Distronic and
the distance warning function are turned
on or off.
Press button
è
or
ÿ
repeatedly
until you see one of the following dis-
plays.
Warning!
G
An intermittent warning sounds and the
Distronic warning lamp
l
in the instru-
ment cluster 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 your vehicle to increase
the distance between your vehicle and the
vehicle in front of you. The warning sound is
intended as a final caution that you have not
interceded with your own braking inputs to
avoid a potentially dangerous situation. Do
not wait for the operation of the warning sig-
nal to intercede with your own braking, as
that will result in potentially dangerous
emergency braking which will not always re-
sult in an impact being avoided.
Tailgating increases the risk of an accident.
Warning!
G
Distronic brakes your vehicle with a maxi-
mum of 6.5 ft/s
2 (2 m/s
2). This corre-
sponds to about 20% of the maximum
deceleration ability of your vehicle.
Distronic brakes the vehicle in an effort to
restore the preset distance or to maintain
the speed. The brake pedal is automatically
applied as this happens which results in the
brake pedal moving.
Keep driver’s foot area clear at all times, in-
cluding the area under the brake pedal. Ob-
jects stored in this area may impair pedal
movement which could interfere with the
braking ability of the Distronic system.
Do not place your foot under the brake pedal
– your foot could become caught.

203 Controls in detail
Driving systems
Distronic deactivated
If Distronic is deactivated, the standard
display of Distronic appears in the multi-
function display.
1Vehicle ahead, if detected
2Actual distance to vehicle ahead
3Should-be distance to vehicle ahead
4Symbol for activated distance warning
function
5Your vehicleDistronic activated
When you turn Distronic on, you will see
the set speed in the multifunction display
for about five seconds. If Distronic is
activated, you can see the following dis-
play in the multifunction display.
1Distronic activatedCruise control lever
The Distronic system is operated by means
of the cruise control lever.
The cruise control lever is the uppermost
lever found on the left-hand side of the
steering column.
1Set current or higher speed
2Set current or lower speed
3Deactivate Distronic
4Resume at previously set speed

205 Controls in detail
Driving systems
Setting a lower speed
Briefly tip the cruise control lever in the
direction of arrow2 (
page 203) to
decrease vehicle speed in increments
of 5 mph (Canada: 10 km/h)
The new speed is set.
The stored speed is displayed in the multi-
function display for approximately five sec-
onds (
page 203), and one or two
segments around the stored speed light up
on the speedometer (
page 201).Fine adjustment in 1 mph
(Canada: 1 km/h) increments
Faster

Briefly tip the cruise control lever in the
direction of arrow4 (
page 203).Setting to last stored speed (“Resume”
function)

Briefly tip the cruise control lever in the
direction of arrow4 (
page 203).
Distronic is set to the last stored
speed.

Remove your foot from the accelerator
pedal.
iWhen you use the cruise control lever
to decelerate, the transmission will au-
tomatically downshift if the rate of de-
celeration is too low.
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 preset
speed could cause an accident and/or seri-
ous injury you and others.

206 Controls in detailDriving systemsDeactivating Distronic
There are several ways to deactivate the
Distronic system:
Briefly tip the cruise control lever in the
direction of arrow3 (
page 203).
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 78) or you de-
activate the ESP


you move the transmission selector le-
ver into positionN
A signal will sound. The
DISTRONIC OFF

message appears in the multifunction
display for approximately five seconds.Setting the following distance in
Distronic
You can set the specified following dis-
tance for Distronic by varying the time set-
ting between 1.0 and 2.0 seconds. Using
this time setting and the current speed of
your vehicle, Distronic calculates and sets
the required following distance to the vehi-
cle ahead. The set distance will be shown
in the multifunction display field.
The thumbwheel for making the time set-
ting is located on the lower section of the
center console.
iThe following message will appear in
the multifunction display for approxi-
mately five seconds:
DISTRONIC OFF
.
The 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 approximately
25 mph (40 km / h) by operation of the sys-
tem. At that time the driver must apply the
brakes in order to reduce vehicle speed fur-
ther or bring it to a stop.

207 Controls in detail
Driving systems
1Distance warning function on/off
switch
2Thumbwheel for setting distanceIncreasing distance
Increasing the distance setting causes Dis-
tronic to maintain a greater following dis-
tance to the vehicle ahead.

Turn thumbwheel 2 towards
¯
.
Decreasing distance
Decreasing the distance setting causes
Distronic to maintain a shorter following
distance to the vehicle ahead.

Turn thumbwheel2 towards
®
.Distance warning function
When Distronic is deactivated, this func-
tion will continue to warn you when recog-
nizing a stationary obstacle or a slower
vehicle moving in the vehicle’s path and
the danger of a collision exists:


The distance warning lamp
l
in the
instrument cluster lights up.


An intermittent warning sounds.
If these warnings are issued, you must
brake manually to maintain a safe distance
and avoid a collision with the vehicle
ahead.
When pressing the brake pedal, the warn-
ing sound stops. The warning sound also
stops when the distance to the vehicle
ahead is sufficient again without applying
the brake pedal. In this case the distance
warning lamp also extinguishes.
Warning!
G
I t is up t o t he d ri ver to exer c is e di s cr et io n 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.

208 Controls in detailDriving systems
Activating
Press switch1.
The indicator lamp on the switch lights
up. A loudspeaker symbol appears in
the multifunction display (
page 203).
Deactivating

Press switch1.
The indicator lamp on the switch goes
out.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 which will
deactivate the Distronic system.
Warning!
G
If the Distronic warning lamp
l
in the in-
strument cluster lights up 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, then your vehicle could accelerate
to the previously selected speed.


209 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, Dis-
tronic will switch off, and the message DISTRONIC - CLEAN SENSOR! SEE
OPERATOR’S MAN.
appears in the multifunc-
tion display.
For cleaning and care of the Distronic sen-
sor, see “Cleaning the Distronic* system
sensor cover” (page 285).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.
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.

iIf the message
DISTRONIC - CLEAN
SENSOR! SEE OPERATOR’S MAN.
disap-
pears during driving and the last speed
stored flashes for approximately five
seconds, the dirt (e.g. slush) has dis-
solved; Distronic is again operational.