BMW 328i xDrive Sports Wagon 2011 - Manual (Page 90)

Technology for driving comfort and safety
88
Flat Tire Monitor FTM*
The concept
The system does not measure the actual infla-
tion pressure in the tires.
The system detects a tire pressure loss due to
speed comparisons among the individual
wheels as you drive.
In the event of pressure loss, the rolling circum-
ference changes and, thus, the rotating speed
of the affected wheel. The system detects this
and reports it as a flat tire.
Functional requirement
The system has to have been initialized at the
correct inflation pressure; otherwise, a reliable
reporting of a flat tire is not assured.
Each time a tire inflation pressure has been cor-
rected or a wheel or tire has been changed,
reinitialize the system.
System limitations
It is impossible to provide advance warn-
ing of sudden, severe tire damage caused
by outside influences. <
The system will not detect a natural, uniform
pressure loss in all four tires. Therefore you
should check the inflation pressure regularly.
In the following situations, the system could be
delayed or malfunction:
> System has not been initialized
> Driving on snowy or slippery road surface
> Performance-oriented style of driving: slip
in the drive wheels, high lateral acceleration
> Driving with snow chains *
Status display
The current status of the Flat Tire Monitor can
be displayed on the Control Display, e.g.
whether or not the FTM is active.
1. "Vehicle Info"
2. "Vehicle status"
3. "Flat Tire Monitor"
The status is displayed.
Initialization
In the initialization, the set inflation pressures
are adopted as reference values for the detec-
tion of a flat tire. The initialization is begun by
confirmation of the inflation pressures.
Do not initialize the system while snow chains
are attached.
1. "Vehicle Info"
2. "Vehicle status"
3. "Reset"
4. Start the engine – do not drive away.
5. Start the initialization using "Reset".
6. Start driving.
The initialization is completed during driv-
ing, which can be interrupted at any time.
When driving resumes, the initialization is con-
tinued automatically.
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