Flat tire monitor ftm, Technology for comfort, convenience and safety – BMW X3 xDrive30i 2009 User Manual

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Technology for comfort, convenience and safety

After releasing the brake, start driving immedi-
ately; otherwise, the acceleration assistant will
no longer hold the vehicle after approx.
2 seconds and the vehicle will start to roll back-
ward.

Malfunction

The warning lamp for the brake system
lights up in yellow. The acceleration
assistant has failed. The vehicle will not

be held after the brake is released. Have the
system checked as soon as possible.

Flat Tire Monitor FTM*

The concept

The Flat Tire Monitor detects a pressure loss in
a tire based on comparing the speeds of the
individual wheels while driving.
In the event of a pressure loss, a change occurs
in the rolling circumference and therefore the
rotation speed of the corresponding wheel.
This change is detected and signaled as a flat
tire.

Functional requirement

To ensure the reliable signaling of a flat tire, the
system must be initialized at the correct tire
inflation pressure.

The initialization must be carried out after
each correction of the tire inflation pres-

sure and after every tire or wheel change.

System limits

The Flat Tire Monitor cannot predict sud-
den severe tire damage caused by out-

side factors and does not detect a natural, even
pressure drop in all four tires.

In the following situations, the system could be
delayed or malfunction:

When the system has not been initialized

When driving on snow-covered or slippery
road surfaces

Sporty driving style: slip in the drive wheels,
high lateral acceleration.

When driving with snow chains

When driving with a compact wheel, the Flat
Tire Monitor cannot operate.

Initializing system

The initialization is completed while driv-
ing and can be interrupted at any time.

The initialization automatically continues when
driving resumes.
Do not initialize the system when driving with
snow chains

or with a compact wheel.

Start the engine just before driving, but do
not begin to drive.

Press the button for at least 4 seconds, but
not longer than 2 minutes. After the button
is released, the indicator lamp in the instru-
ment cluster lights up yellow for a few sec-
onds.

Begin driving.
The initialization is completed while driving,
without requiring any further input from you.

Indication of a flat tire

The warning lamp lights up red. In addi-
tion, an acoustic signal sounds. There is
a flat tire or extensive inflation pressure

loss.

Reduce speed and stop the vehicle care-
fully. Avoid sudden braking and steering
maneuvers.

Identify damaged tire.

If identification is not possible, con-
tact your BMW Sports Activity Vehi-

cle Center.

Replace the damaged wheel, refer to
Wheel changes on page

116