BMW X3 Owners Manual: The concept
The system detects tire inflation pressure loss on the basis of rotation speed differences between the individual wheels while driving.
In the event of a tire inflation pressure loss, the diameter and therefore the rotational speed of the corresponding wheel changes. This will be detected and reported as a flat tire.
The system does not measure the actual inflation pressure in the tires.
Functional requirements
The system must have been initialized when the tire inflation pressure was correct; otherwise, reliable flagging of a flat tire is not assured.
Initialize the system after each correction of the tire inflation pressure and after every tire or wheel change.
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 (FTM)"
The status is displayed.
Initialization
When initializing the once set inflation tire
pressures serve as reference values in order to
detect a flat tire. Initialization is started by confi ...
Other materials:
BMW X3 Service & Repair Manual > Wheel bearings and stub axle: Replacing bearing for front wheel
Necessary preliminary tasks:
Remove FRONT WHEEL .
If necessary, remove visual protection cap (1).
Release collar bolt (1), press brake pedal to floor for this purpose.
Installation note:
Renew collar bolt (1) and compression spring (2).
Pay attention to installation position of co ...
BMW X3 Owners Manual
BMW X3 Service & Repair Manual
