BMW F12 2011 Technical Training Manual page 34

F12￿Chassis￿Dynamics
4.￿Brakes
• Brake￿pedal￿applied,￿or
• Automatic￿transmission￿parking￿lock￿engaged,￿or
• Clutch￿pedal￿depressed￿(vehicles￿with￿manual￿gearbox￿only).
That￿prevents￿the￿vehicle￿starting￿to￿roll￿when￿not￿intended,￿e.g.￿if￿another￿occupant￿apart￿from￿the
driver￿presses￿the￿parking￿brake￿button.￿Once￿the￿parking￿brake￿is￿released,￿the￿red￿indicator￿lamp￿on
the￿instrument￿panel￿(KOMBI)￿and￿the￿red￿LED￿in￿the￿parking￿brake￿button￿go￿out.
Activation￿of￿the￿EMF￿actuator￿sets￿the￿spindle￿in￿motion.￿The￿rotation￿of￿the￿spindle￿moves￿the￿spin-
dle￿nut￿a￿small,￿defined￿distance￿away￿from￿the￿brake￿piston.
Dynamic￿emergency￿braking
The￿law￿requires￿that￿there￿are￿two￿operating￿facilities￿for￿the￿brakes.￿The￿second￿operating￿facility
in￿the￿F12￿after￿the￿brake￿pedal￿is￿the￿parking￿brake￿button￿in￿the￿center￿console.￿If￿the￿parking￿brake
button￿is￿pulled￿up￿while￿the￿vehicle￿is￿moving,￿the￿DSC￿system￿performs￿a￿dynamic￿emergency￿brak-
ing￿operation￿in￿a￿defined￿sequence.￿This￿function￿is￿intended￿for￿emergency￿situations￿in￿which￿the
driver￿is￿not￿able￿to￿brake￿the￿vehicle￿using￿the￿brake￿pedal.￿Other￿occupants￿can￿also￿bring￿the￿vehicle
to￿a￿standstill￿in￿this￿way￿if,￿for￿example,￿the￿driver￿suddenly￿falls￿unconscious.
During￿dynamic￿emergency￿braking,￿brake￿pressure￿is￿generated￿hydraulically￿at￿all￿four￿wheel￿brakes.
The￿DSC￿functions￿are￿fully￿active￿and￿the￿brake￿lights￿are￿operated.￿That￿represents￿a￿fundamental
advantage￿over￿manual￿parking￿brakes.
Dynamic￿emergency￿braking￿only￿occurs￿while￿the￿parking￿brake￿button￿is￿being￿pulled.￿The￿level￿of
deceleration￿applied￿by￿the￿DSC￿is￿steeply￿increased.￿During￿dynamic￿emergency￿braking￿the￿EMF￿in-
dicator￿light￿on￿the￿instrument￿panel￿(KOMBI)￿is￿activated.￿In￿addition,￿a￿Check￿Control￿message￿is￿dis-
played￿along￿with￿an￿acoustic￿signal￿in￿order￿to￿draw￿the￿driver's￿attention￿to￿this￿special￿situation.
If￿the￿driver￿decelerates￿by￿pressing￿the￿brake￿pedal￿and￿pulling￿the￿parking￿brake￿button￿at￿the￿same
time,￿the￿DSC￿control￿unit￿priorities￿and￿implements￿the￿higher￿braking￿demand.￿If￿dynamic￿emergen-
cy￿braking￿continues￿until￿the￿vehicle￿is￿at￿a￿standstill,￿the￿vehicle￿remains￿braked￿even￿after￿the￿park-
ing￿brake￿button￿is￿released.￿The￿EMF￿indicator￿light￿in￿the￿instrument￿panel￿(KOMBI)￿remains￿on.￿The
driver￿can￿then￿release￿the￿parking￿brake￿(see￿"Releasing￿the￿parking￿brake").
Parking￿brake￿fault
If￿the￿parking￿brake￿develops￿a￿fault,￿the￿EMF￿indicator￿lamp￿in￿the￿instrument￿panel￿(KOMBI)￿shows
yellow.￿A￿Check￿Control￿message￿is￿displayed.
F12￿Indicator￿light￿showing￿parking￿brake￿fault
Emergency￿release
No￿provision￿is￿made￿for￿the￿customer￿to￿release￿the￿parking￿brake￿in￿emergencies.
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