3 Series E92 325xi (N53) COUPE
The brake pedal is frequently not depressed strongly enough in emergency braking situations. The ABS
feedback control range is not reached (or not on all 4 wheels).
The return pump increases the brake pressure until ABS regulation is activated:
-
If the brake pedal is depressed quickly with insufficient pedal pressure (recognised from the signal from the
brake pressure sensors)
-
If the brake pedal is depressed slowly and then with greater braking deceleration than necessary
(recognised from the signal from the brake pressure sensors), when both front wheels have reached the
ABS control threshold.
Example of a typical situation:
The traffic slows, making light braking necessary at first, but then demands as short a stopping distance as
possible.
RPA: Run Flat Indicator
RPA is not a driving dynamic function.
DSC uses the Run Flat Indicator (RPA) to monitor the tyre 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 tyre 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 tyre 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.
Initialisation is started manually. Then (after a journey has started), initialisation runs automatically. In other
words, the circumference of individual tyres are recorded and evaluated.
The initialisation phase lasts approx. 5 to 15 minutes for the individual speed ranges.
[for further information, please refer to SI Technology (SBT) 36 01 04 078]
CBS: Condition Based Service
CBS is not a driving dynamic function.
Condition Based Service, as the name suggests, is a means of ensuring that the car is serviced as and when
necessary. CBS comprises various maintenance operations, e.g. engine oil and brake pads.
The remaining distance for the front and back brake pads are calculated separately in the DSC control unit.
When making the calculation, the condition of the brake pad wear sensors is taken into account (reference point
at 6 mm and 4 mm).
[for further information, please refer to SI Technology (SBT) 00 01 04 070]
New functions for DSC Mk60E5
Brake Standby through pre-tensioning of the brakes in an emergency
Pre-tensioning the brakes shortens the brakes' response time.
If the accelerator pedal is rapidly released (accelerator pedal angle), the brakes are immediately pretensioned.
DSC generates a low braking pressure through the "analogised" solenoid valves, without creating any
measurable deceleration of the vehicle. The working clearance between the brake pads and brake disks is
equalised. If the brakes are not applied within a certain time, this preliminary brake pressure is cancelled. The
early pre-tensioning of the brake pads is active at road speeds greater than 70 km/h.
SBT Dynamic Stability Control Mk60E5 E85, E86, E87, E90, E91, E92, E93
BMW AG - TIS
30.01.2013 05:02
Issue status (12/2007) Valid only until next DVD is issued
Copyright
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