2008 MERCEDES-BENZ SL550 brake sensor

218 Controls in detail
Driving systems
Distronic*
When activated, the Distronic adaptive
cruise control system increases the driving
convenience afforded by the cruise control
while traveling on expressways and other
major roadways.

If the Distronic distance sensor detects
a slower moving vehicle directly ahead,
your vehicle’s speed will be reduced so
that you follow that vehicle at the pre-
set following distance.

If there is no vehicle directly ahead of
you, Distronic will function in the same
way as standard cruise control
(
page 214).
Warning!G
Distronic adaptive cruise control is not a
substitute for active driving involvement. It
does not react to pedestrians or stationary
objects, recognize or predict the lane curva-
ture nor the movement of preceding
vehicles.
Distronic 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 the road, weather and traffic
conditions. In addition, the driver must pro-
vide the steering, braking and other driving
inputs necessary to remain in 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 responsibility for the vehicle’s speed,
distance to the preceding vehicle and, most
importantly, brake operation to assure a
safe stopping distance, always remains with
the driver.
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.
Warning!G
Distronic cannot take street and traffic con-
ditions into account. Only use Distronic if
the road, weather and traffic conditions
make it advisable to travel at a constant
speed.

227 Controls in detail
Driving systems
Driving with Distronic
This section describes a number of driving
situations where special precaution is
required on the part of the driver.
Be prepared to brake in such situations.
This will deactivate the Distronic system.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 Currently Unavailable See
Oper. Manual
appears in the multifunction
display.
For cleaning and care of the Distronic sen-
sor, see “Cleaning the Distronic* system
sensor cover” (
page 336).
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 your
set distance. This means that:

Your vehicle can pass another vehicle
after you have changed lanes.

While in a sharp turn or if the preceding
vehicle is in a sharp turn, Distronic could
lose sight of the preceding vehicle. Your
vehicle could then accelerate to the pre-
viously set 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 alert, observe all
traffic and intercede as required by means
of steering or braking the vehicle.
Warning!G
Distronic should not be used in snowy or icy
road conditions.
iIf the message DISTRONIC Currently
Unavailable See Oper. Manual
disappears
from the multifunction display during driving, the
dirt (e.g. slush) has dissolved. Distronic is avail-
able again if you reactivate it (
page 223).

233 Controls in detail
Driving systems
Suspension for sporty driving style
The setting for sporty driving is selected
when indicator lamp2 is on.
Press button1.
Indicator lamp2 comes on.
Suspension for regular driving style
The setting for regular driving is selected
when indicator lamp2 is off.
Press button1.
Indicator lamp2 goes out.
Parktronic system* (Parking assist)
The Parktronic system is an electronic aid
with ultrasonic sensors. It is designed to
assist the driver during parking maneu-
vers. It visually and audibly indicates the
relative distance between the vehicle and
an obstacle.
The Parktronic system is automatically
activated when you switch on the ignition,
release the parking brake, or place the
gear selector lever in position D, R, or N.
Warning!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 remains 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 337).
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.
!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.

234 Controls in detail
Driving systems
The Parktronic system deactivates at
speeds exceeding approximately
11 mph (18 km/h). At lower vehicle
speeds the Parktronic system turns on
again. The Parktronic system also deacti-
vates when you place the gear selector le-
ver in position P or depress the parking
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 bumperRange of the sensorsFront sensors
Rear sensorsiTo 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 337).
Centerapprox. 40 in (100 cm)
Cornersapprox. 24 in (60 cm)
Centerapprox. 48 in (120 cm)
Cornersapprox. 32 in (80 cm)
!During parking maneuvers, pay special at-
tention 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 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.

306 Operation
Tires and wheels
The TPMS only functions on wheels that
are equipped with the proper electronic
sensors. It monitors the tire inflation pres-
sure, as selected by the driver, in all four
tires. A warning is issued to alert you to a
decrease in pressure in one or more of the
tires.
Warning!G
The TPMS does not indicate a warning for
wrongly selected inflation pressures. Always
adjust tire inflation pressure according to
the Tire and Loading Information placard on
the driver’s door B-pillar or, if available, the
supplemental tire inflation pressure infor-
mation on the inside of the fuel filler flap.
The TPMS is not able to issue a warning due
to a sudden dramatic loss of pressure (e.g.
tire blowout caused by a foreign object). In
this case bring the vehicle to a halt by care-
fully applying the brakes and avoiding
abrupt steering maneuvers.
Warning!G
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
Tire and Loading Information placard on the
driver’s door B-Pillar or, if available, the tire
inflation pressure label on the fuel filler flap.
If your vehicle has tires of a different size
than the size indicated on the Tire and
Loading Information placard or, if available,
the tire inflation pressure label, you should
determine the proper tire inflation pressure
for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitor-
ing system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires is significantly underinflated. Accord-
ingly, when the low tire pressure telltale illu-
minates, you should stop and check your
tires as soon as possible, and inflate them to
the proper pressure. Driving on a signifi-
cantly underinflated tire causes the tire to
overheat and can lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehi-
cle’s handling and stopping ability. Please
note that the TPMS is not a substitute for
proper tire maintenance, and it is the
driver’s responsibility to maintain correct
tire pressure, even if underinflation has not
reached the level to trigger illumination of
the TPMS low tire pressure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate
when the system is not operating properly.
The TPMS malfunction indicator is com-
bined with the low tire pressure telltale.
When the system detects a malfunction, the
telltale will flash for approximately
one minute and then remain continuously
illuminated. This sequence will continue
upon subsequent vehicle start-ups as long
as the malfunction exists. When the mal-
function indicator is illuminated, the system
may not be able to detect or signal low tire
pressure as intended.

350 Practical hints
What to do if …
ProblemPossible cause/consequenceSuggested solution
EThe white Distronic* indicator
lamp comes on while driving.The Distronic* distance sensor has recog-
nized a preceding vehicle.
EThe red distance warning 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
recognized a stationary obstacle on
your probable line of travel.
Apply the brakes immediately.
Carefully observe the traffic situation.
You may need to brake or maneuver
to avoid hitting an obstacle.
AThe yellow fuel tank reserve
warning lamp lights when the
engine is running.The fuel level has dropped below the reserve
mark.Refuel at the next gas station
(
page 279).
The fuel filler cap is not closed tightly.Check the fuel filler cap (page 279).

375 Practical hints
What to do if …
Left displayRight displayPossible cause/consequencePossible solution
Tire Pressure Monitor
Wheel Sensor MissingVehicles with Advanced TPMS*:
One or more wheels without
appropriate wheel sensors
mounted (e.g. spare wheel).
The respective tire is indicated by
--- instead of the tire inflation
pressure in the multifunction
display.
Have the Advanced TPMS* checked by an
authorized Mercedes-Benz Center.
Have appropriate wheel sensors installed
by an authorized Mercedes-Benz Center.
Tire Pressure MonitorCurrently
UnavailableThe TPMS or Advanced TPMS* is
unable to monitor the tire pres-
sure due to a nearby radio interfer-
ence source.As soon as the causes for the malfunction
are no longer present, the TPMS or
Advanced TPMS* automatically becomes
active again after a few minutes driving.
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.
Warning!G
Follow recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly,
adversely affect handling and fuel economy,
and are more likely to fail from being over-
heated.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride
comfort, wear unevenly, increase stopping
distance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road
debris, potholes etc.

392 Practical hints
What to do if …
Left displayRight displayPossible cause/consequencePossible solution
FKey Detected
In VehicleA SmartKey with KEYLESS-GO* left
in the vehicle was recognized while
locking the vehicle from the out-
side.Take the SmartKey with KEYLESS-GO* out of
the vehicle.
.3rd Brake LampThe high mounted brake lamp is
malfunctioning. This message will
only appear if a critical number of
LEDs have stopped working.Contact an authorized Mercedes-Benz Center
as soon as possible.
AUTO Light
InoperativeThe light sensor is malfunctioning.
The headlamps switch on automati-
cally.Contact an authorized Mercedes-Benz Center
as soon as possible.
To switch off the headlamps (U.S. vehicles only):
In the control system, set lamp operation to
manual mode (
page 163).
Switch on headlamps using the exterior lamp
switch (
page 131).
Brake Lamp
Left
Auxiliary Bulb OnThe left brake lamp is malfunction-
ing. An auxiliary bulb has been
brought into use.Contact an authorized Mercedes-Benz Center
as soon as possible.
Brake Lamp
Right
Auxiliary Bulb OnThe right brake lamp is malfunction-
ing. An auxiliary bulb has been
brought into use.Contact an authorized Mercedes-Benz Center
as soon as possible.