Page 253 of 305

Vehicle care251Tyre pressure monitoringsystem
The tyre pressure monitoring system checks the pressure of all four tyres
once a minute when vehicle speed
exceeds a certain limit.Caution
Tyre pressure monitoring system
warns only about low tyre pressure condition and does not replace
regular tyre maintenance by the
driver.
All wheels must be equipped with pressure sensors and the tyres must
have the prescribed pressure.
Note
In countries where the tyre pressure
monitoring system is legally
required, the use of wheels without
pressure sensors will invalidate the
vehicle operating permit.
The current tyre pressures can be
shown in the Driver Information
Centre.
Midlevel display:
Select the Tyre pressure page under
the Vehicle Information Menu ? in
the Driver Information Centre 3 115.
Uplevel display:
Select the Tyre pressure page under
the Info Menu in the Driver
Information Centre 3 115.
System status and pressure warnings
are displayed by a message
indicating the corresponding tyre in
the Driver Information Centre.
The system considers the tyre
temperature for the warnings.
Temperature dependency 3 249.
A detected low tyre pressure
condition is indicated by the control
indicator w 3 112.
If w illuminates, stop as soon as
possible and inflate the tyres as
recommended 3 285.
If w flashes for 60-90 seconds then
illuminates continuously, there is a
fault in the system. Consult a
workshop.
Page 254 of 305

252Vehicle careAfter inflating, some driving may be
required to update the tyre pressure
values in the Driver Information
Centre. During this time w may
illuminate.
If w illuminates at lower temperatures
and extinguishes after driving, this
could be an indicator for approaching
a low tyre pressure condition. Check
tyre pressure.
Vehicle messages 3 122.
If the tyre pressure must be reduced
or increased, switch off ignition.
Only mount wheels with pressure
sensors, otherwise the tyre pressure
will not be displayed and w
illuminates continuously.
A spare wheel or temporary spare
wheel is not equipped with pressure
sensors. The tyre pressure
monitoring system is not operational
for these tyres. Control indicator w
illuminates. For the further three
tyres, the system remains
operational.The use of commercially-available
liquid tyre repair kits can impair the
function of the system. Factory-
approved repair kits can be used.
Operating electronic devices or being close to facilities using similar wave
frequencies could disrupt the tyre
pressure monitoring system.
Each time the tyres are replaced, tyre
pressure monitoring system sensors
must be dismounted and serviced. For the screwed sensor, replace
valve core and sealing ring. For the
clipped sensor, replace complete
valve stem.
Use only original plastic valve caps to protect valve on any damage.Caution
Do not use metal valve caps as
they lead to valve oxidation and
damage.
Vehicle loading status
Adjust tyre pressure to load condition
according to the tyre information label or tyre pressure chart 3 285, and
select the appropriate setting in Tyre
Load within the Vehicle Information
Menu 3 115. This setting determines
the reference pressures for the tyre
pressure warnings.
The Tyre Load menu only appears
when the vehicle is at a standstill and the parking brake is applied. On
vehicles with automatic transmission
the selector lever must be in P.
Midlevel display:
Select the Tyre load page under the
Vehicle Information Menu ? in the
Driver Information Centre 3 115.
Page 255 of 305

Vehicle care253Select● Light for comfort pressure up to
three people.
● Eco for Eco pressure up to three
people.
● Max for full loading.
Uplevel display:
Select the Tyre load page under the
Options Menu in the Driver
Information Centre 3 115.
Select
● Light for comfort pressure up to
three people.
● Eco for Eco pressure up to
three people.
● Max for full loading.
Auto learn function After changing wheels or wheel
positions the vehicle must be
stationary for approx. 20 minutes,
before the system recalculates. The
following relearn process takes up to
10 minutes of driving in a speed range
of 40 to 100 km/h. Avoid to drive
outside of this range for a longer time.
If possible, use a country road or
similar which allows continuous
driving. During relearn process $
can be displayed or pressure values
can swap in the Driver Information Centre.
Ensure the tyre loading status is set
according to the selected pressure
3 115.If problems occur during the relearn
process, a failure message is
displayed in the Driver Information
Centre. w will flash for 60 seconds
and then illuminate continuously.
If this happens, repeat learning
process. Keep your vehicle stationary for approx. 20 minutes and then drive
again for 10 minutes as described
above.
Tread depth
Check tread depth at regular
intervals.
Tyres should be replaced for safety
reasons at a tread depth of 2-3 mm
(4 mm for winter tyres).
For safety reasons, it is
recommended that the tread depth of
the tyres on one axle should not vary
by more than 2 mm.
Page 304 of 305

302Tyre pressures ........................... 285
Tyre repair kit ............................. 255
U Ultrasonic parking assist............. 195
Upholstery .................................. 269
Uplevel display ........................... 115
USB port ....................................... 99
Using this manual ..........................3
V Vehicle battery ........................... 228
Vehicle checks............................ 224
Vehicle data ................................ 277
Vehicle data recording and privacy ..................................... 294
Vehicle detected ahead ..............114
Vehicle dimensions .................... 283
Vehicle identification number ....275
Vehicle jack ................................ 247
Vehicle messages .....................122
Vehicle personalisation .............124
Vehicle security ............................ 37
Vehicle specific data ......................3
Vehicle storage ........................... 223
Vehicle tools ............................... 247
Vehicle unlocking ........................... 6 Ventilating ..................................... 56W
Warning chimes .........................123
Warning lights ............................. 104
Warning triangle .......................... 88
Washer and wiper systems .........14
Washer fluid ............................... 227
Wheel changing .........................258
Wheel covers ............................. 254
Wheels and tyres .......................249
Windows ....................................... 42
Windscreen................................... 42
Windscreen wiper and washer ....94
Winter tyres ............................... 249
Wiper blade replacement ..........230