ensure that a warning message will only
appear if the tyre pressure drops significantly.
The tyre pressure monitor does not warn you of an incorrectly set tyre pressure. Observe
the notes on the recommended tyre pressure
(Y page 380).
The tyre pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the
tyre 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
abrupt steering manoeuvres.
The tyre pressure monitor has a yellow warn-
ing lamp in the instrument cluster for indicat- ing a pressure loss or malfunction. Depending
on how the warning lamp flashes or lights up, a tyre pressure that is too low or a malfunc-
tion in the tyre pressure monitor is indicated:
R if the warning lamp is lit continuously, the
tyre pressure on one or more tyres is sig-
nificantly too low. The tyre pressure moni-
tor is not malfunctioning.
R if the warning lamp flashes for around a
minute and then remains lit constantly, the tyre pressure monitor is malfunctioning.
In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(Y page 295).
It may take up to ten minutes for a malfunc-
tion of the tyre pressure monitor to be indi-
cated. A malfunction will be indicated by the
tyre pressure warning lamp flashing for
approximately one minute and then remain-
ing lit. When the fault has been rectified, the
tyre pressure warning lamp goes out after you
have driven for a few minutes.
The tyre pressure values indicated by the on- board computer may differ from those meas-
ured at a filling station using a pressure
gauge. The tyre pressures shown by the on-
board computer refer to those measured at
sea level. At high altitudes, the tyre pressure
values indicated by a pressure gauge are
higher than those shown by the on-board computer. In this case, do not reduce the tyre
pressures.
The operation of the tyre pressure monitor
can be affected by interference from radio
transmitting equipment (e.g. radio head-
phones, two-way radios) that may be being
operated in or near the vehicle.
Checking the tyre pressure electroni-
cally X
Make sure that the key is in position 2in the
ignition lock (Y page 161).
X Press the òbutton on the steering
wheel to call up the list of menus.
X Press 9or: on the steering wheel
to select the Service Servicemenu.
X Press the abutton.
X Press 9or: to select Tyre pres‐
Tyre pres‐
sure
sure .
X Press the abutton.
The current tyre pressure for each wheel
will be displayed in the multifunction dis-
play.
If the vehicle was parked for longer than
20 minutes, the Tyre Tyrepressures
pressures will
willbe
be
displayed after a few minutes of
displayed after a few minutes of
driving driving message appears.
After a teach-in period, the tyre pressure
monitor automatically detects new wheels or new sensors. As long as a clear allocation of
the tyre pressure values to the individual
wheels is not possible, the Tyre pressure Tyre pressure
monitor active
monitor active message is shown instead
of the tyre pressure display. The tyre pres-
sures are already being monitored. 382
Tyre pressureWheels and tyres
Warning messages of the tyre pressure
monitor If the tyre pressure monitor detects a pres-
sure loss in one or more tyres, a warning mes-
sage is shown in the multifunction display and the yellow tyre pressure monitor warning
lamp comes on.
R If the Please correct tyre pressure
Please correct tyre pressure
message appears in the multifunction dis-
play, the tyre pressure in at least one tyre is too low and must be corrected at the next
opportunity.
R If the Check tyre(s)
Check tyre(s) message appears in
the multifunction display, the tyre pressure
in one or more tyres has dropped signifi-
cantly and the tyres must be checked.
R If the Warning tyre defect
Warning tyre defect message
appears in the multifunction display, the
tyre pressure in one or more tyres has drop-
ped suddenly and the tyres must be
checked.
Observe the instructions and safety notes in
the display messages in the "Tyres" section
(Y page 295).
If the wheel positions on the vehicle are inter-
changed, the tyre pressures may be displayed for the wrong positions for a short time. After
a few minutes of driving, this is rectified and
the tyre pressures are displayed for the cor-
rect positions.
Restarting the tyre pressure monitor When you restart the tyre pressure monitor,
all existing warning messages are deleted and
the warning lamps go out. The monitor uses
the currently set tyre pressures as the refer-
ence values for monitoring. In most cases, the tyre pressure monitor will automatically
detect the new reference values after you
have changed the tyre pressure. However,
you can also define reference values man-
ually as described here. The tyre pressure
monitor then monitors the new tyre pressure values. X
Use the table on the inside of the fuel filler
flap to ensure that the tyre pressure is set
correctly in all four tyres for the current
operating conditions.
Also observe the notes in the section on
tyre pressures (Y page 380).
X Make sure that the key is in position 2in the
ignition lock.
X Press the òbutton on the steering
wheel to call up the list of menus.
X Press 9or: on the steering wheel
to select the Service Servicemenu.
X Press the abutton.
X Press 9or: to select Tyre pres‐
Tyre pres‐
sure
sure .
X Press the abutton.
The current tyre pressure for each wheel or
the Tyre pressures will be dis‐ Tyre pressures will be dis‐
played
played after
aftera
afew
few minutes
minutes of
ofdriv‐
driv‐
ing
ing message will be displayed in the mul-
tifunction display.
X Press the :button.
The Use current pressures as new
Use current pressures as new
reference values
reference values message appears in
the multifunction display.
If you wish to confirm the restart:
X Press the abutton.
The Tyre press. monitor restarted
Tyre press. monitor restarted
message appears in the multifunction dis-
play.
After you have driven for a few minutes, the
system checks whether the current tyre
pressures are within the specified range.
The new tyre pressures are then accepted
as reference values and monitored.
If you wish to cancel the restart:
X Press the %button.
The tyre pressure values stored at the last
restart will continue to be monitored. Tyre pressure
383Wheels and tyres Z
vehicle to a halt by braking carefully. Avoid
abrupt steering manoeuvres.
The function of the tyre pressure loss warning system is limited or delayed if:
R snow chains are fitted to your vehicle's
tyres.
R road conditions are wintry.
R you are driving on sand or gravel.
R you adopt a very sporty driving style (cor-
nering at high speeds or driving with high
rates of acceleration).
R you are driving with a heavy load (in the
vehicle or on the roof).
Restarting the tyre pressure loss warn-
ing system Restart the tyre pressure loss warning system
if you have:
R changed the tyre pressure
R changed the wheels or tyres
R fitted new wheels or tyres
X Before restarting, make sure that the tyre
pressures are set properly on all four tyres
for the respective operating conditions.
The recommended tyre pressures can be
found in the table on the fuel filler flap.
The tyre pressure loss warning system can only give reliable warnings if you have set
the correct tyre pressure. If an incorrect
tyre pressure is set, these incorrect values
will be monitored.
X Observe the notes in the section on tyre
pressures (Y page 380).
X Make sure that the key is in position 2in the
ignition lock (Y page 161) .
X Press the òbutton on the steering
wheel to call up the list of menus.
X Press 9or: on the steering wheel
to select the Service
Service menu.
X Press the abutton. X
Press 9or: to select Tyre pres‐ Tyre pres‐
sure
sure .
X Press the abutton.
The Run Flat Indicator active
Run Flat Indicator active
Restart
Restart with
withOK
OKmessage appears in the
multifunction display.
If you wish to confirm the restart: X Press the abutton.
The Tyre pressure now OK?
Tyre pressure now OK? message
appears in the multifunction display.
X Press 9or: to select Yes
Yes .
X Press the abutton.
The Run Flat Indicator restarted
Run Flat Indicator restarted
message appears in the multifunction dis-
play.
After a teach-in period, the tyre pressure
loss warning system will monitor the set
tyre pressures of all four tyres.
If you wish to cancel the restart:
X Press the %button.
or
X If the Tyre pressure now OK? Tyre pressure now OK? message
appears, press 9or: to select
Cancel
Cancel .
X Press the abutton.
The tyre pressure values stored at the last
restart will continue to be monitored. Changing a wheel
Flat tyre
You can find information on what to do in the event of a flat tyre in the "Breakdown assis-
tance" section (Y page 358). Information on
driving with MOExtended tyres in the event of a flat tyre can be found under "Breakdown
assistance" (Y page 358). Changing a wheel
385Wheels and tyres Z
Interchanging the wheels
G
WARNING
Interchanging the front and rear wheels may
severely impair the driving characteristics if
the wheels or tyres have different dimensions. The wheel brakes or suspension components may also be damaged. There is a risk of acci-
dent.
Interchange front and rear wheels only if the
wheels and tyres are of the same dimensions.
! On vehicles fitted with a tyre pressure
monitor, electronic components are loca-
ted in the wheel.
Tyre-fitting tools should not be applied in
the area of the valve, as this could damage
the electronic components.
Only have tyres changed at a qualified spe- cialist workshop.
Interchanging the front and rear wheels of
differing dimensions can render the general
operating permit invalid.
Observe the instructions and safety notes in
the "Fitting a wheel" section (Y page 386).
The wear patterns on the front and rear tyres differ depending on the operating conditions.Interchange the wheels before a clear wear
pattern has formed on the tyres. Front tyres
typically wear more on the shoulders and the
rear tyres in the centre.
On vehicles that have the same size front and
rear wheels, you can interchange the wheels
every 5,000 to 10,000 km depending on the
degree of tyre wear. Ensure the direction of
rotation is maintained.
Clean the contact surfaces of the wheel and
the brake disc thoroughly every time a wheel is interchanged. Check the tyre pressure and,
if necessary, restart the tyre pressure loss
warning system (Y page 385) or the tyre pres-
sure monitor (Y page 383) . Direction of rotation
Tyres with a specified direction of rotation
have additional benefits, e.g. if there is a risk of aquaplaning. These advantages can only begained if the tyres are fitted corresponding to
the direction of rotation.
An arrow on the sidewall of the tyre indicates
its correct direction of rotation. Storing wheels
Store wheels in a cool, dry and preferably
dark place if they are not being used. Protect the tyres against oil, grease, petrol and diesel. Fitting a wheel
Preparing the vehicle X
Stop the vehicle on solid, non-slippery and
level ground.
X Apply the electric parking brake manually.
X Move the front wheels to the straight-
ahead position.
X Shift the transmission to position P.
X Make sure that "normal" level is selected
for AIRMATIC (Y page 210).
X Switch off the engine.
X Open the driver's door.
The on-board electronics now have status
0. This is the same as the key having been
removed.
X Remove the Start/Stop button from the
ignition lock (Y page 161).
or, if the key is inserted in the ignition lock: X Remove the key from the ignition lock.
X If included in the vehicle equipment,
remove the tyre-change tool kit from the
vehicle.
X Safeguard the vehicle against rolling away.
i Apart from some country-specific var-
iants, vehicles are not equipped with tyre-
changing tools. Some tools for changing a 386
Changing a wheelWheels and ty
res