The tire pressure monitor has a yellow warn-
ing lamp in the instrument cluster for indicat-
ing a pressure loss or malfunction. Whether
the warning lamp flashes or lights up indi-
cates whether a tire pressure is too low or the
tire pressure monitor is malfunctioning:
Rif 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.
Rif the warning lamp flashes for around a
minute and then remains lit constantly, the
tire pressure monitor is malfunctioning.
In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(
Ypage 200).
It may take up to ten minutes for a malfunc-
tion of the tire pressure monitor to be indica-
ted. A malfunction will be indicated by the tire
pressure warning lamp flashing for approx-
imately one minute and then remaining lit.
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-
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.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in position
2 in the ignition lock (
Ypage 137).
XPress the =or; button on the steer-
ing wheel to select the Service
menu.
XPress the9or: button to select
Tire Pressure
.
XPress 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.
If an emergency spare wheel is mounted, the
system may continue to show the tire pres-
sure of the wheel that has been removed for a few minutes. If this occurs, note that the value
displayed for the position where the spare
wheel is mounted is not the same as the cur-
rent tire pressure of the emergency spare
wheel.
Tire pressure monitor warning mes-
sages
If the tire pressure monitor detects a pressureloss in one or more tires, a warning message
is shown in the multifunction display and the
yellow tire pressure monitor warning lamp
comes on.
RIf the Correct Tire Pressuremessage
appears in the multifunction display, the
tire pressure in at least one tire is too low
296Tire pressure
Wheels and tires
and must be corrected at the next oppor-
tunity.
RIf theCheckTiresmessage appears in the
multifunction display, the tire pressure in
one or more tires has dropped significantly
and the tires must be checked.
RIf the Warning Tire Malfunctionmes-
sage appears in the multifunction display,
the tire pressure in one or more tires has
dropped suddenly and the tires must be
checked.
Observe the instructions and safety notes in
the display messages in the "Tires" section
(
Ypage 200).
If the wheel positions on the vehicle are rota-
ted, the tire pressures may be displayed for
the wrong positions for a short time. This is
rectified after a few minutes of driving, and
the tire pressures are displayed for the cor-
rect positions.
Restarting the tire pressure monitor
When you restart the tire pressure monitor, all
existing warning messages are deleted and
the warning lamps go out. The monitor uses
the currently set tire pressures as the refer-
ence values for monitoring. In most cases, the
tire pressure monitor will automatically
detect the new reference values after you
have changed the tire pressure. However, you
can also define reference values manually as described here. The tire pressure monitor
then monitors the new tire pressure values.
XSet the tire pressure to the value recom-
mended for the corresponding driving sit-
uation on the Tire and Loading Information
placard on the driver's side
B-pillar (
Ypage 291).
Additional tire pressure values for different
loads can also be found on the tire pressure
table on the inside of the fuel filler flap
(
Ypage 291).
XMake sure that the tire pressure is correct
on all four wheels.
XMake sure that the SmartKey is in position
2 in the ignition lock.
XPress the =or; button on the steer-
ing wheel to select the Service
menu.
XPress the9or: button to select
Tire Pressure
.
XPress the abutton.
The multifunction display shows the cur-
rent tire pressure for the individual tires or
the Tire
pressurewillbedisplayed
after driving a few minutesmes-
sage.
XPress the :button.
The Use Current Pressures as New
Reference Valuesmessage appears in
the multifunction display.
If you wish to confirm the restart:
XPress the abutton.
The Tire Press. Monitor Restarted
message appears in the multifunction dis-
play.
After driving for a few minutes, the system
checks whether the current tire pressures
are within the specified range. The new tire
pressures are then accepted as reference
values and monitored.
If you wish to cancel the restart:
XPress the %button.
The tire pressure values stored at the last
restart will continue to be monitored.
Radio type approval for the tire pres-
sure monitor
In certain countries, a radio type approval for
the tire pressure monitor may be required.
The radio type approval number for the tire
pressure monitor can be found in the "Wheels
and tires" section of the Digital Operator's
Manual.
Tire pressure297
Wheels and tires
Z
XBring the front wheels into the straight-
ahead position.
XShift the transmission to positionP.
XVehicles with AIRMATIC: make sure that
"normal" level is selected (
Ypage 166).
XSwitch off the engine.
XRemove the SmartKey from the ignition
lock.
or, on vehicles with KEYLESS ‑GO:
XOpen the driver's door.
The on-board electronics now have status
0. This is the same as the SmartKey having
been removed.
XRemove the Start/Stop button from the
ignition lock (
Ypage 138).
XIf included in the vehicle equipment,
remove the tire-change tool kit from the
vehicle (
Ypage 270).
XSafeguard the vehicle against rolling away.
Securing the vehicle to prevent it from
rolling away
If your vehicle is equipped with a wheel chock,
it can be found in the tire-change tool kit
(
Ypage 270).
The folding wheel chock is an additional
safety measure to prevent the vehicle from
rolling away, for example when changing a
wheel.
XFold both plates upwards :.
XFold out lower plate;.
XGuide the lugs on the lower plate fully into
the openings in base plate =.
Securing the vehicle on level ground (example:
Sedan)
XOn level ground:place chocks or other
suitable items under the front and rear of
the wheel that is diagonally opposite the
wheel you wish to change.
Securing the vehicle on slight downhill gradients
(example: Sedan)
XOn light downhill gradients: place
chocks or other suitable items in front of
the wheels of the front and rear axle.
Raising the vehicle
GWARNING
If you do not position the jack correctly at the
appropriate jacking point of the vehicle, the
jack could tip over with the vehicle raised.
There is a risk of injury.
Only position the jack at the appropriate jack-
ing point of the vehicle. The base of the jack
must be positioned vertically, directly under
the jacking point of the vehicle.
310Changing a wheel
Wheels and tires
Emergency spare wheel
Important safety notes
GWARNING
The wheel or tire size as well as the tire type of the spare wheel or emergency spare wheel
and the wheel to be replaced may differ.
Mounting an emergency spare wheel may
severely impair the driving characteristics.
There is a risk of an accident.
To avoid hazardous situations:
Radapt your driving style accordingly and
drive carefully.
Rnever mount more than one spare wheel or
emergency spare wheel that differs in size.
Ronly use a spare wheel or emergency spare
wheel of a different size briefly.
Rdo not switch ESP®off.
Rhave a spare wheel or emergency spare
wheel of a different size replaced at the
nearest qualified specialist workshop.
Observe that the wheel and tire dimensions
as well as the tire type must be correct.
When using an emergency spare wheel or
spare wheel of a different size, you must not
exceed the maximum speed of 50 mph
(80 km/h).
Snow chains must not be mounted on emer-
gency spare wheels.
General notes
You should regularly check the pressure of
the emergency spare wheel, particularly prior
to long trips, and correct the pressure as nec-
essary (
Ypage 291). The value on the wheel is
valid. In addition, the emergency spare wheel
tire pressure can be found under "Technical
data" (
Ypage 332).
An emergency spare wheel may also be
mounted against the direction of rotation.
Observe the time restriction on use as well as
the speed limitation specified on the emer-
gency spare wheel. Replace the tires after six years at the latest,
regardless of wear. This also applies to the
emergency spare wheel.
iWhen you are driving with the emergency
spare wheel mounted, the tire pressure
monitor cannot function reliably. Only
restart the tire pressure monitor when the
defective wheel has been replaced with a
new wheel.
If an emergency spare wheel is mounted,
the system may continue to show the tire
pressure of the wheel that has been
removed for a few minutes. The value dis-
played for the mounted emergency spare
wheel is not the same as the current tire
pressure of the emergency spare wheel.
"Minispare" emergency spare wheel/ collapsible spare wheel
Opening the stowage well
Sedan: the emergency spare wheel can be
found in the stowage well under the trunk
floor.
XLift the trunk floor upwards (Ypage 248).
Wagon: the emergency spare wheel is loca-
ted in the stowage well under the cargo com-
partment floor.
XRemove the seat cushions of the folding
bench seat; see the Digital Operator's Man-
ual, keyword "Folding bench seat (cargo
compartment)".
XLift the cargo compartment floor up.
Emergency spare wheel329
Wheels and tires
Z
XRemove theprotective sheet from th evehi-
cle tool ki tand pull it ove rth ecollapsible
spar ewheel.
XStow th ecollapsible spar ewhee lin th e
emergenc yspar ewhee lwell under th e
trunk/carg ocompartment.
Inflating th ecollapsible spar ewheel
!
Inflat eth ecollapsible spar ewhee lusin g
th etire inflation compressor before lower -
in g th evehicle. The whee lrim could other -
wise be damaged.
!Do no toperate th etire inflation compres-
sor for longer than eigh tminute sat atime
without abreak. It may otherwise overheat .
The tire inflation compressor can be oper -
ate dagain once it has cooled down .
XMountth ecollapsible spar ewhee las
described (
Ypage 309).
The collapsible spar ewhee lmus tbe moun -
te dbefore it is inflated.
XPull connecto r? and th ehos eout of th e
housing.
XRemove th ecap from th evalv eon th ecol-
lapsible spar ewheel.
XScrew union nut :of th ehos eonto th e
valve.
XMak esur eon/off switch Aof th etire
inflation compressor is set to 0.
XInsertconnecto r? into a12 Vsocke t
(
Ypage 251) in your vehicle.
XTurn th eSmartKey to position 1in th eigni-
tion loc k (
Ypage 137).
XPress on/off switch Aon th etire inflation
compressor to I.
The tire inflation compressor is switched
on .The tire is inflated. The tire pressur eis
shown on pressur egauge =.
XInflateth etire to th especified tire pres-
sure.
The specified tire pressur eis printed on th e
yellow label of th eemergenc yspar ewheel.
XWhe nth especified tire pressur ehas been
reached, press on/off switch Aon th e
electric air pump to 0.
The tire inflation compressor is switched
off .
XTurn th eSmartKey to position 0in th eigni-
tion lock.
XIf th etire pressur eis higher than th especi-
fie dpressure, press pressur erel ease va
lv e
butto n; until th ecorrec ttire pressur ehas
been reached.
XUnscrew air hos eunion nut :from th e
valve.
XScrew th ecap onto th evalv eof th ecol-
lapsible spar ewhee lagain .
XStow connecto r? and th ehos ein th e
lower section of th etire inflation compres-
sor .
XStow th etire inflation compressor in th e
vehicle.
Emergency spare wheel331
Wheels and tires
Z