Vehicle care221Temperature dependencyThe tyre pressure depends on the
temperature of the tyre. During
driving, tyre temperature and
pressure increase. Tyre pressure
values provided on the tyre
information label and tyre pressure
chart are valid for cold tyres, which
means at 20 °C.
The pressure increases by nearly
1.5 psi for a 10 °C temperature
increase. This must be considered
when warm tyres are checked.
Tyre deflation detectionsystem
The tyre deflation detection system continually checks the rotation speed
of all four wheels and warns on low
tyre pressure condition once vehicle
is driving. This is achieved by
comparing tyre rolling circumference
with reference values and further
signals.
If a tyre loses pressure the control
indicator w illuminates and a warning
message is displayed in the Driver
Information Centre.In this case reduce speed, avoid
sharp cornering and strong braking.
Stop at next safe opportunity and
check tyre pressure.
Control indicator w 3 96.
After adjusting tyre pressure initialise
system to extinguish the control
indicator and restart system.Caution
Deflation detection system warns
just about low tyre pressure
condition and does not replace
regular tyre maintenance by the
driver.
In case of a system malfunction a
message is displayed in the Driver
Information Centre. Set correct tyre
pressure and reinitialise system. If the
failure continues to be displayed,
contact a workshop. The system is
inoperable when ABS or ESC has a
malfunction or a temporary spare
wheel is used. Once the road tyre has
been refitted, check the tyre pressure with cold tyres and initialise the
system.
System initialisation
After tyre pressure correction or
wheel change, the system must be
initialised to learn new circumference reference values:
1. Always ensure that all four tyres have correct tyre pressure3 255.
2. Apply parking brake. 3. Press w to reset deflation
detection system.
4. Reset is confirmed by pop-up indication.
222Vehicle careAfter initialisation system
automatically calibrates to new tyre
pressures during driving. After longer
drive the system will adopt and
monitor new pressures.
Always check tyre pressure with cold
tyres.
System has to be reinitialised when: ● Tyre pressure has been changed
● Load condition has been changed
● Wheels have been swapped or exchanged
The system will not warn
instantaneously on a tyre blow out or a rapid deflation. This is due to
required calculation time.
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.
The legally permissible minimum
tread depth (1.6 mm) has been
reached when the tread has worn
down as far as one of the tread wear
indicators (TWI). Their position is
indicated by markings on the
sidewall.
If there is more wear at the front than
the rear, swap round front wheels and rear wheels periodically. Ensure that
the direction of rotation of the wheels
remains the same.
Tyres age, even if they are not used.
We recommend tyre replacement
every 6 years.
Changing tyre and wheel
size
If tyres of a different size than those
fitted at the factory are used, it may be necessary to reprogramme the tyre
deflation detection system and make
other vehicle modifications.
Tyre deflation detection system
3 221.
Have the label with tyre pressures
replaced.9 Warning
The use of unsuitable tyres or
wheels may lead to accidents and will invalidate the vehicle
operating permit.
