brake BMW X5 2002 E53 DSC System User Guide

BRAKE FLUID LEVEL WARNING SWITCH
A new fluid level switch is incorporated into the reservoir cap.
• With sufficient fluid level the reed contact is closed.
• When level drops below allowable limits, switch opens.
Since the normal position is closed, this circuit is monitored
for shorts to + and ground.
The LCM constantly monitors the input. If the ground signal is momentary,the LCM sig-
nals the Instrument cluster of the condition. The instrument cluster then informs the DSC
III control module over the CAN bus. If the signal is received just prior to the activation of
the charge pump, the charge pump activation is delayed.
If the signal is present for more then 25 seconds, the LCM issues two I BUS message for
the Instrument Cluster:
1. Post “Brake Fluid Level” in the Matrix display
2. Notify the DSC III via CAN that the Fluid level has been low for more than 25 seconds.
The DSC III control module immediately switches DSC III functions off and continuously illu-
minates the DSC indicator in the cluster.
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