BMW E87 2009, Руководство пользователя, Страница: 76 / 248

Tech
nic
al featu
res fo
r dr
iving comfort and
safety
74
the drive-off assistant will no longer hold the
vehicle in place and the car will start to roll back-
wards.
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Run Flat Indicator RPA
The principle
The Run Flat Indicator detects a pressure drop
in a tyre on the basis of a speed comparison
between the individual wheels while the vehicle
is being driven.
If a tyre loses pressure, its rolling circumference
changes, and this in turn alters the speed of
rotation of the corresponding wheel. This
change is detected and interpreted as a punc-
ture.
Operating requirements
The system has to be initialised with all four
tyres inflated to the correct pressures in order
for it to respond reliably in detecting a puncture.
The system has to be reinitialised every
time tyre pressures are corrected, after
each change of a wheel or tyre, and after a trailer
has been attached or detached.
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System limitations
The Run Flat Indicator is unable to warn
the driver of sudden, severe tyre damage
caused by external factors, nor can it identify
the gradual loss of pressure that will inevitably
occur in all four tyres over a lengthy period of
time.
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In the following situations, the system could be
slow to respond or operate incorrectly:
> System was not initialised
>
Driving on snow-covered or slippery sur-
faces
> Sporty style of driving: high slip at the drive
wheels, high lateral acceleration
> Snow chains are fitted
Initialising the system
Initialisation is completed while the vehi-
cle is in motion, however, this can be
interrupted at any time. Initialisation resumes
automatically as soon as the car starts moving
again.
Do not initialise the system while snow chains
are fitted.
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1. "Vehicle information"
2. "Vehicle status"
3. "Confirm tyre pressure"
4. Start the engine – do not drive off.
5. Start the initialisation with "Confirm tyre
pressure".
6. Drive off.
Initialisation is completed while the vehicle is in
motion. "Status: Flat Tyre Monitor active" then
appears again on the Control Display.
Indication of a flat tyre
The warning light shows red. A mes-
sage appears on the Control Display.
An acoustic signal also sounds.
There is a flat tyre or substantial loss of tyre
pressure.
1. Reduce your speed and cautiously stop the
car.
2. Check whether your vehicle is equipped
with normal tyres or with run-flat tyres.
The symbol identifying run-flat tyres
is a circle with the letters RSC on the
sidewall, see page 183 . <
Normal tyres
1. Determine which wheel is damaged.
If you cannot tell which wheel is dam-
aged, please contact your BMW Serv-
ice. <
Online Edition for Part no. 01 41 2 602 816 - © 08/09 BMW AG Online Edition for Part no. 01 41 2 602 816 - © 08/09 BMW AG