BMW 320d xDrive, Owner'S Handbook Manual

Page: 61 / 145

Technical features for driving comfort and safety
60
cle's load or if towing a trailer, the vehicle may
roll backwards a little during this time. After
releasing the brake pedal, drive off without
delay. After approx. 2 seconds, the drive-off
assistant will no longer hold the vehicle in place
and the car will start to roll backwards.
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Malfunction
The warning lights for the brake sys-
tem show yellow. The drive-off
assistant has failed. The vehicle will
not be held in place after the brake
pedal is released. Have the system checked as
soon as possible.
Run Flat Indicator RPA
The principle
The Run Flat Indicator monitors the pressures
in the four tyres fitted to the wheels while the
car is being driven. The system reports any sig-
nificant 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.
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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: causing the driven
wheels to spin, high lateral acceleration
>
If snow chains are fitted
Initialising the system
Initialisation completes 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.
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1. Start the engine immediately before setting
off, but do not drive off yet.
2. Lightly push button 1 in the turn indicator
stalk repeatedly up or down until the appro-
priate symbol appears in the display,
accompanied by the word "INIT".
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.
Online Edition for Part-No. 01 41 0 159 204 - © 03/05 BMW AG