
Driving systems
ProblemPossible causes/consequences andMSolutions
·
The red distance warn-
ing lamp lights up while
the vehicle is in motion.The distance to the vehicle in front is too small for the speed
selected.
X Increase the distance.
·
The red distance warn-
ing lamp lights up while
the vehicle is in motion. A warning tone also
sounds.You are approaching a vehicle or a stationary obstacle in your lineof travel at too high a speed.
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to
brake or take evasive action.
Further information on DISTRONIC PLUS ( Ypage 117).
Wa rning and indi cator lamps in the instrument cluster169
On-board computer and displays
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Useful information
iThese operating instructions describe all
the standard and optional equipment of
your COMAND system, as available at the
time of going to print. Country-specific dif- ferences are possible. Please note that
your COMAND system may not be equip-
ped with all the features described. This
also applies to safety-related systems and
functions.
iRead the information on qualified special-
ist workshops: ( Ypage 28).
General notes
The COMAND section in these operating
instructions describes the basic principles for
operation. More information can be found in
the Digital Operator's Manual.
Important safety notes
GWARNING
Modifications to electronic components, their
software as well as wiring can impair their
function and/or the function of other net-
worked components. In particular, systems
relevant to safety could also be affected. As a
result, these may no longer function as inten-
ded and/or jeopardize the operating safety of
the vehicle. There is an increased risk of an
accident and injury.
Never tamper with the wiring as well as elec-
tronic components or their software. You
should have all work to electrical and elec-
tronic equipment carried out at a qualified
specialist workshop.
If you make any changes to the vehicle elec-
tronics, the general operating permit is ren-
dered invalid.
GWARNING
If you operate information systems and com-
munication equipment integrated in the vehi- cle while driving, you will be distracted from
traffic conditions. You could also lose controlof the vehicle. There is a risk of an accident.
Only operate the equipment when the traffic
situation permits. If you are not sure that this
is possible, park the vehicle paying attention
to traffic conditions and operate the equip-
ment when the vehicle is stationary.
You must observe the legal requirements for
the country in which you are currently driving when operating COMAND.
COMAND calculates the route to the destina-
tion without taking account of the following,
for example:
R traffic lights
R stop and yield signs
R merging lanes
R parking or stopping in a no parking/no
stopping zone
R other road and traffic rules and regulations
R narrow bridges
COMAND can give incorrect navigation com-
mands if the actual street/traffic situation
does not correspond with the digital map's
data. Digital maps do not cover all areas nor
all routes in an area. For example, a route may have been diverted or the direction of a one-
way street may have changed.
For this reason, you must always observe
road and traffic rules and regulations during
your journey. Road and traffic rules and reg-
ulations always have priority over the sys-
tem's driving recommendations.
Navigation announcements are intended to
direct you while driving without diverting your
attention from the road and driving.
Please always use this feature instead of con-
sulting the map display for directions. Look-
ing at the icons or map display can distract
you from traffic conditions and driving, and
increase the risk of an accident.
172Important safety notes
COMAND

Please note that the TPMS is not a substitutefor proper tire maintenance, and it is the driv-
er'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.
USA only:
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate if the
system is not operating properly. The TPMS
malfunction indicator is combined with the
low tire pressure telltale. When the system
detects a malfunction, the warning lamp will
flash for approximately a minute and then
remain continuously illuminated. This
sequence will be repeated every time the vehi- cle is started as long as the malfunction
exists.
When the malfunction indicator is illuminated,
the system may not be able to detect or signal low tire pressure as intended. TPMS malfunc-
tions may occur for a variety of reasons,
including the mounting of incompatible
replacement or alternate tires or wheels on
the vehicle that prevent the TPMS from func-
tioning properly. Always check the TPMS mal-
function telltale after replacing one or more
tires or wheels on your vehicle to ensure that
the replacement or alternate tires and wheels allow the TPMS to continue to function prop-erly.
It is the driver's responsibility to set the tire
pressure to the recommended cold tire pres-
sure suitable for the operating situation( Y page 232). Note that the correct tire pres-
sure for the current operating situation must
first be taught-in to the tire pressure monitor. If there is a substantial loss of pressure, the
warning threshold for the warning message isaligned to the reference values taught-in.
Restart the tire pressure monitor after adjust-
ing to the cold tire pressure ( Ypage 238).
The current pressures are saved as new ref-
erence values. As a result, a warning message
will appear if the tire pressure drops signifi-
cantly. The tire pressure monitor does not warn you
of an incorrectly set tire pressure. Observe
the notes on the recommended tire pressure
( Y page 232).
The tire pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the
tire is penetrated by a foreign object. In the
event of a sudden loss of pressure, bring the
vehicle to a halt by braking carefully. Avoid
sudden steering movements.
In order to check the tire pressure, the vehi-
cle's wheels are installed with sensors that
monitor the tire pressure in all four tires. The
tire pressure monitor warns you if the pres-
sure drops in one or more of the tires. The tire pressure monitor only functions if the correct
sensors are installed on all wheels.
The tire pressure monitor has a yellow warn-
ing lamp in the instrument cluster for indicat- ing pressure loss/malfunctions (USA) or
pressure loss (Canada). Whether the warning
lamp flashes or lights up indicates whether a
tire pressure is too low or the tire pressure
monitor is malfunctioning:
R if the warning lamp is lit continuously, the
tire pressure on one or more tires is signif-
icantly too low. The tire pressure monitor is not malfunctioning.
R USA only: if the warning lamp flashes for
around a minute and then remains lit con-
stantly, the tire pressure monitor is mal-
functioning.
Information on tire pressures is displayed in
the multifunction display. After a few minutes of driving, the current tire pressure of each
tire is shown in the multifunction display.
USA only: the tire pressure warning lamp will
inform you of a malfunction in the tire pres-
sure monitor by flashing for approximately
one minute and then remaining lit. It may take
more than ten minutes before the data menu
is displayed. When the malfunction has been
rectified, the tire pressure warning lamp goes out after a few minutes of driving.
The tire pressure values indicated by the on-
board computer may differ from those meas-
236Tire pressure
Wheels and tires

ured at a gas station with a pressure gauge.
The tire pressures shown by the on-board
computer refer to those measured at sea
level. At high altitudes, the tire pressure val-
ues indicated by a pressure gauge are higher
than those shown by the on-board computer. In this case, do not reduce the tire pressures.
The operation of the tire pressure monitor can
be affected by interference from radio trans-
mitting equipment (e.g. radio headphones,
two-way radios) that may be being operated
in or near the vehicle.
iUSA only:
This device complies with part 15 of the
FCC Rules. Operation is subject to the fol-
lowing two conditions:
1. This device may not cause harmful inter- ference, and
2. This device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
iCanada only:
This device complies with RSS-210 of
Industry Canada. Operation is subject to
the following two conditions:
1. This device may not cause harmful inter- ference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
Checking the tire pressure electroni-cally
X Make sure that the SmartKey is in posi-
tion 2in the ignition lock ( Ypage 103).
X Press the =or; button on the steer-
ing wheel to select the
Serv.menu. X
Press the 9or: button to select
Tire Pressure.
X Press the abutton.
The current tire pressure of each tire is
shown in the multifunction display.
If the vehicle has been parked for over
20 minutes, the
Tire pressure will be
displayed after driving a few
minutesmessage appears.
After a teach-in process, the tire pressure
monitor automatically detects new wheels or
new sensors. As long as a clear allocation of
the tire pressure value to the individual
wheels is not possible, the
Tire Pressure
Monitor Activedisplay message is shown
instead of the tire pressure display. The tire
pressures are already being monitored.
iIf a spare wheel is mounted, the system
may continue to show the tire pressure of
the wheel that has been removed for a few minutes. Observe that the displayed value
is not the same as the current tire pressure
of the emergency spare wheel.
Tire pressure monitor warning mes-
sages
If the tire pressure monitor detects a signifi-
cant pressure loss on one or more tires, a
warning message is shown in the multifunc-
tion display. A warning tone also sounds and
the tire pressure warning lamp lights up in the
instrument cluster.
Each tire that is affected by a significant loss of pressure is highlighted in the pressure dis-
play.
X If the
Correct Tire Pressuremessage
appears in the multifunction display, check the tire pressure on all four wheels and cor-
rect it if necessary.
X If the
CheckTiresmessage appears in the
multifunction display, the tire pressure in
one or more tires has dropped significantly and the tires must be checked.
X If the
Tire Press. Warning Caution
Tire Malfunctionmessage appears in
Tire pressure237
Wheels and ti res
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