Technical features for driving comfort and safety
74
Run Flat Indicator RPA
The principle
The Run Flat Indicator monitors the pressures
in the tyres while the car is being driven. The
system reports any significant loss of pressure
in one tyre in relation to another.
If a tyre loses pressure its rolling radius
changes, and this in turn alters the speed of
rotation. This alteration is detected and inter-
preted as a puncture.
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.<
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.<
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 car is
on the move, but 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.<
Operating principle, see page 64.
1. Start the engine immediately before setting
off, but do not drive off yet.
2. Lightly push button 1 in the turn indicator
lever up or down repeatedly until the corre-
sponding symbol and the word "RESET"
are displayed.
3. Press button 2 to confirm your choice of the
Run Flat Indicator.
4. Press button 2 and hold it down for approx.
5 seconds, until the reading shown below is
displayed.
5. Drive off.
Initialisation is completed while the car is on
the move, without any feedback.
Indication of a flat tyre
The warning light shows red. In addi-
tion, an acoustic signal is emitted.
There is a flat tyre or substantial loss
of tyre pressure.
1. Carefully reduce your speed to no more
than 80 km/h or 50 mph. Avoid violent or
sudden braking and steering manoeuvres.
Do not exceed a speed of 80 km/h or
50 mph after this.
If the car is not fitted with run-flat
tyres, see page 120, the standard
Online Edition for Part no. 01 41 0 013 257 - © 02/07 BMW AG
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