Runflat indicator – BMW AG User Manual

Page 84

Runflat Indicator*

The principle

The Runflat Indicator system monitors
tyre pressures at all four road wheels
when the car is being driven. The sys-
tem reports any sudden, significant loss
of pressure in one tyre in relation to the
others.

Tyre pressures are monitored by meter-
ing the relative speeds of the four
wheels. If these relative speeds diverge
from certain ratios the system interprets
this deviation as a puncture and reacts
accordingly.

System requirements

The procedure outlined below has to be
adopted in order to teach the Runflat
Indicator to recognise the correct tyre
pressures:

1. Check the pressures of all the tyres

and correct as necessary, see
page

2. Initialise the system.

System limitations

The Runflat Indicator is unable to
provide advance warning of seri-

ous, sudden tyre damage due to exter-
nal influences and is unable to detect
the natural, gradual and uniform loss of
pressure in all four tyres.

In the following situations, recognition
of tyre-pressure loss might be delayed,
or the system may even be rendered
non-operational:
> When the car is driven on snow-cov-

ered roads or slippery surfaces

> If your style of driving is sporty: slip at

the drive wheels, high lateral acceler-
ation

> When snow chains are fitted to the

wheels, the system could issue false
alarms or fail to detect a deflated tyre

> The Runflat Indicator cannot function

when you drive with the compact
spare wheel fitted.

Initialising the system

Always reinitialise the system
immediately after correcting tyre

pressures, changing a tyre, or fitting
new wheels. The procedure requires
driving the car over a certain distance.

1. Start the engine, but do not drive off

just yet

2. Press and hold down the button, but

not for longer than 10 seconds at a
time, until the yellow telltale light in
the instrument cluster lights up for a
few seconds

3. Drive off.

It takes a few minutes before the Run-
flat Indicator is able to detect and
report deflated tyres.