Vehicle care157Tyre pressure monitoringsystem
The Tyre Pressure Monitoring
System (TPMS) uses radio and
sensor technology to check tyre
pressure levels.Caution
Tyre pressure monitoring system
warns only about low tyre pressure condition and does not replace
regular tyre maintenance by the
driver.
The TPMS sensors monitor the air pressure in the tyres and transmit tyre
pressure readings to a receiver
located in the vehicle.
All wheels must be equipped with
pressure sensors and the tyres must
have the prescribed pressure.
Tyre pressure chart 3 185.
Note
In countries where the tyre pressure monitoring system is legally
required, the use of wheels without
pressure sensors will invalidate the
vehicle type approval.
Low tyre pressure condition
A detected low tyre pressure
condition is indicated by illumination
of control indicator w 3 86 together
with a warning chime. In vehicles with Multifunction version of the Driver
Information Centre, a corresponding message is also displayed.
If w illuminates, stop as soon as
possible and inflate the tyres as
recommended 3 185.
After inflating, driving may be
required to update the tyre pressure
values in the system. During this time
w may illuminate.
If w illuminates at lower temperatures
and extinguishes after some driving,
this could be an indicator for
approaching a low tyre pressure
condition. Check tyre pressure of all
four tyres.
If the tyre pressure must be reduced
or increased, switch off ignition.
Only mount wheels with pressure
sensors, otherwise the tyre pressure
value cannot be recognised by the
system and w flashes for several
seconds then illuminates
continuously. In vehicles with
Multifunction version of the Driver Information Centre, a corresponding
message is also displayed.
158Vehicle careA spare wheel or temporary spare
wheel is not equipped with pressure
sensors. TPMS is not operational for
these wheels. For the further three
wheels, TPMS remains operational.
Spare wheel 3 163, Wheel changing
3 162.
Control indicator w and (depending
on version) a corresponding message appears at each ignition cycle untilthe tyres are inflated to the correct
tyre pressure.
Driver Information Centre 3 89.
Relearn function
After changing wheels, TPMS needs
to recalculate. The relearn process
takes up to 20 minutes of driving with
a minimum speed of 20 km/h.
If problems occur during the relearn
process, control indicator w flashes
for several seconds then illuminates
continuously and (depending on
version) a warning message is
displayed in the Driver Information
Centre.
Driver Information Centre 3 89.General information
The use of tyre chains or
commercially available liquid tyre
repair kits can impair the function of
the system. Factory-approved tyre
repair kits can be used.
Tyre repair kit 3 159, Tyre chains
3 159.
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, TPMS sensors must be dismounted
and serviced by a workshop.
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
is the same as before.
Tyres age, even if they are not used.
We recommend tyre replacement
every six years.
