System functions: Initialization

Initialization is started manually (e.g. by pressing the RPA button). Once it has been started, initialization will continue through to complete calibration. This process may be interrupted any number of times.

It is important that the vehicle is driven away immediately after initialization is started. The system will not start calibration until the vehicle is driven away. Even a terminal change will not change this.

In principle, calibration is only possible while the vehicle is being driven (road speeds above 25 km/h).

Initialization will run as a fully automatic calibration sequence (after the journey has started). In other words, the circumference of individual tires are recorded and evaluated.

To allow a drop in tire pressure to be detected, the system considers different speed ranges and driving situations. Taking account of the driving situation means that the system has to be primed for each speed range individually.

From 09/2004 (starting with E87), these speed ranges and driving situations have been combined into 3 calibration ranges. This means greater clarity for output via the BMW diagnosis systems Group Tester One (GT1) and DISplus.

The initialization phase lasts approx. 5 to 15 minutes for the individual speed ranges. The end of the initialization phase is not indicated.

A visual and acoustic warning can only be emitted in the speed ranges that have been calibrated by at least 67 percent.

The calibration process can be delayed by:

• dynamic driving
• a road with lots of bends
• frequent changes in load (only on vehicles with electronic height control -> air spring/height control regulation)