MERCEDES-BENZ S500 2002 W220 Owner's Manual

268 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
The distance warning sound continues until the driver
activates the brake pedal, or the preset distance is
obtained. As soon as the preset distance is obtained, the
distance warning lamp goes out.Caution!
If the driver’s foot is not fully removed from the
accelerator pedal, the message “DISTRONIC OVERRIDE”
appears in the multifunction display. The Distronic
control system will be overridden and it will not
regulate the preset vehicle speed and following
distance. The vehicle speed and following distance is
determined only by the accelerator pedal position.
Distronic works on steep uphill and downhill gradients
by downshifting gears and applying the brakes to
maintain the speed selected by the driver. The
transmission will upshift again once the gradient evens
out.
The speed can be increased (e.g. for passing) by using
the accelerator. After the accelerator is released, the
previously set speed will be resumed automatically.
Distronic is deactivated if a vehicle in front causes your
vehicle to slow down to less than approx. 25 mph
(Canada: 40 km/h). A signal sounds and the message
“DISTRONIC OFF” appears for 5 seconds in the
multifunction display.
The vehicle speed displayed can briefly vary from the
speed setting of the Distronic system.
Wa r n i n g !
An intermittent warning sounds and the distance
warning lamp in the speedometer 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
capable 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 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 signal to intercede
with your own braking as that will result in
potentially dangerous emergency braking which
will not always result in an impact being avoided.Tailgating increases the risk of an accident.

269 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Additional driving hints
Important!
When starting the engine, Distronic goes through an
initialization and self-test phase – this can take up to
2minutes.
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 will switch off, and the message
“DISTRONIC – CLEAN SENSOR!” appears in the
multifunction display.
For cleaning and care of the Distronic sensor, see
page 386.
Restart the engine after cleaning the sensor.
The following are some sample situations which may
influence the functions of Distronic.
Wa r n i n g !
Distronic works to maintain the speed selected by
the driver unless a moving obstacle proceeding
directly ahead of it in the same travel direction is
detected (e.g. following another vehicle ahead at a
distance 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.Distronic regulates only the distance between your
vehicle and those directly ahead, but does not
register stationary objects in the roadway, e.g.:
• a stopped vehicle in a traffic jam,
• a disabled vehicle,
• an oncoming vehicle.
The driver must always be on the alert and observe
all traffic and intercede with steering and braking
inputs as necessary.Wa r n i n g !
Distronic should not be used in snowy or icy road
conditions.

270 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Traveling through turns or bends in the roadway may
result in Distronic detecting a moving vehicle traveling
in front but not in your lane of travel, causing your
vehicle to brake late or unexpectedly. You must be
prepared to intercede with accelerator or brake
application as necessary.The Distronic system’s detection zone is relatively
narrow at the start and becomes broader as it senses
further from the vehicle. Thus, Distronic may not
recognize another vehicle coming into your path close
to the front of your vehicle. You must be prepared to
intercede with braking or steering as necessary.
A vehicle not traveling directly in front of you could
cause detection problems, the actual distance to that
vehicle really being much shorter.

271 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index A vehicle changing lanes at close range is only
recognized when entering the area scanned by
Distronic. You must apply the service brakes to gain
sufficient distance to the vehicle ahead.A narrow vehicle (e.g. a motorcycle) is only recognized
when entering the area scanned by Distronic. You must
apply the service brakes to gain sufficient distance to
the vehicle ahead.
P54.70-2164-26

272 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Distance warning function
Even if Distronic is deactivated, the distance to the
vehicle ahead continues to be measured, see page 275
for multifunction display.
The Distronic lamp in the speedometer dial illuminates
to advise the driver of a situation which under normal
braking conditions and dry surfaces should have been
addressed by the driver.
The distance warning function can be activated
separately, see page 272. It operates when driving at
speeds above approx. 25 mph (Canada: 40 km/h).
When recognizing a stationary obstacle or a slower
vehicle moving in the vehicle’s path and the danger of a
collision exists, the distance warning lamp in the
speedometer dial lights up and simultaneously an
intermittent warning sounds.
When pressing the service brake pedal, the warning
sound stops. The warning sound also stops, when the
distance to the vehicle ahead is sufficient again without
applying the service brake pedal. In this case the
distance warning lamp also extinguishes.Important!
With Distronic switched off, only the distance warning
function operates, meaning the vehicle does not slow
down.
Distronic does not register oncoming vehicles. Therefore
there is no distance warning.
Important!
Complex driving situations are not always fully
recognized by Distronic, which could result in wrong or
missing distance warnings. See page 269 for additional
driving hints.
Wa r n i n g !
If the distance warning lamp in the speedometer
dial lights up while driving and an intermittent
warning sounds, immediate attention on the part of
the driver is required.As required by the traffic situation, apply the
service brakes and navigate around a possible
obstacle. However, do not drive by relying on the
distance warning function as that will result in an
emergency braking application which, especially
depending on road surface conditions and driver
reaction, will not always be able to avoid a collision.

273 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Distronic settings
1Switch – for distance warning function
2Thumbwheel – for setting distance
Distronic provides a range of following distances to the
vehicle in front. The medium setting is noticeable by a
detent in the center position of the thumbwheel (2).
If you want to:
•Increase distance – turn thumbwheel (2)
towards¯.•Decrease distance – turn thumbwheel (2)
towards®.
To switch the distance warning function on or off:
To switch on – press upper half of switch (1).
The indicator lamp in the switch lights up. If the
Distronic menu is active in the multifunction display, a
loudspeaker symbol appears.
To switch off – press lower half of the switch (1).
The indicator lamp in the switch goes out. If the
Distronic menu is active in the multifunction display,
the loudspeaker symbol disappears.
See page 272 for distance warning function and
page 275 for multifunction displays.
Wa r n i n g !
It is up to the driver to exercise discretion to select
the appropriate setting given road conditions,
traffic, driver’s preferred driving style and
applicable laws and driving recommendations for
safe following distance.

274 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Notes:
With the distance warning function activated, you will
still be advised by an intermittent audible warning if a
potential emergency braking circumstance has been
detected, even if Distronic has been deactivated.
The last selected warning function mode (on/off) will be
stored in memory, even when removing the electronic
key from the starter switch.

275 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Multifunction displays1Distronic is deactivated. The actual distance (5) and
the should-be distance (6) to the vehicle ahead (4)
are displayed.
2Activating Distronic. The display with the selected
speed is shown for approximately 5 seconds.
3Distronic is activated. The message
“DISTRONIC OFF” appears for approximately
5 seconds when Distronic is being deactivated.
4Vehicle ahead.
Only appears if a vehicle is detected ahead.
5Actual distance to vehicle ahead.
6Should-be distance to vehicle ahead (as calculated
by Distronic).
7Own vehicle.
8Distance warning function is activated, see
page 272.
To call up Distronic display:
Press button è or ÿ on the multifunction
steering wheel repeatedly until the display (1 or 3)
appears.

276 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Displays in the speedometer dial
When Distronic system is activated, one or two
segments around the speed stored in memory light up
in the speedometer dial.If a vehicle is detected ahead, those segments in the
speedometer dial light up that indicate the speed range
from the speed of the vehicle in front up to the Distronic
stored speed.
When the vehicle in front can no longer be detected,
only the segments around the stored speed light up. The
vehicle is accelerated to the stored speed.

277 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Brake assist system (BAS)
The BAS is designed to maximize the vehicle’s braking
capability during emergency braking maneuvers by
having maximum power boost applied to the brakes
more quickly in emergency braking conditions than
might otherwise be afforded solely by the driver’s
braking style. This can help reduce braking distances
over what ordinary driving and braking style might do.
The BAS complements the Antilock Brake System (ABS).Applying the brakes very quickly results in maximum
BAS assistance.
To receive the benefit of the system you must apply
continuous full braking power during the stopping
sequence. Do not reduce brake pedal pressure.
Once the brake pedal is released, the BAS is deactivated.
If the BAS warning message is displayed in the
multifunction display, a malfunction has been detected
in the system. The brake system functions in the usual
manner, but without BAS.
With the ABS malfunctioning, the BAS is also switched
off.
If a BAS warning message is displayed in the
multifunction display, have the BAS checked at your
authorized Mercedes-Benz Center as soon as possible.
Wa r n i n g !
BAS cannot prevent the natural laws of physics
from acting on the vehicle, nor can it increase
braking efficiency beyond that afforded by the
condition of the vehicle brakes and tires or the
traction afforded. The BAS cannot prevent
accidents, including those resulting from excessive
speed in turns, following another vehicle too
closely, or aquaplaning. Only a safe, attentive, and
skillful driver can prevent accidents. The
capabilities of a BAS equipped car must never be
exploited in a reckless or dangerous manner which
could jeopardize the user’s safety or the safety of
others.