RPA: Tire Defect Indicator

RPA is not a driving dynamic function.

DSC uses the Run Flat Indicator (RPA) to monitor the tire pressure throughout the journey.

The RPA records the wheel speeds using the wheel-speed sensors of the Dynamic Stability Control (DSC). The RPA compares the speeds of the individual wheels with the average speed. In this way the RPA is able to detect a loss of tire pressure.

The RPA detects a drop in pressure below about 30% +/- 10% of the initial value. The RPA indicator and warning light indicates a drop in tire pressure.

The RPA will indicate this after just a short distance, as a rule after a few minutes, from a certain minimum speed (e.g. 25 km/h) up to the permissible top speed.

Initialization is started manually. Then (after a journey has started), initialization runs automatically. In other words, the circumference of individual tires are recorded and evaluated.

The initialization phase lasts approx. 5 to 15 minutes for the individual speed ranges.