Sensotronic Brake Control (SBC)
327 HO 09 SBC (WJB) 03-05-04
R230 and W211: Starting MY2003
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Objectives At the end of this presentation, you should be able to: 1. Explain Explain the function function of and and p purpos urpose e for for SBC SBC 2. Descri Describe be the the custome customerr interf interface ace with with SBC SBC 3. List the h hydrauli ydraulic c and electronic electronic compone components nts used used for for SBC SBC 4. Describe Describe how how the “normal “normal”” feel of of the brake brake pedal pedal is mainta maintained ined 5. Explain Explain emergen emergency cy operatio operation n of the S SBC BC braking braking system 6. Describ Describe e “temp “temperat erature ure compensa compensatio tion” n” 7. Explain Explain “Deactivat “Deactivation” ion” and and describe describe when itit is necessary necessary to to do itit 8. “Act “Activ ivat ate” e” the the S SBC BC s sys yste tem m 9. Locate tools and tthe he proper proper procedur procedure e for bleeding bleeding brakes brakes
These technical training materials are current as of the date noted on the materials, and may be revised or updated without notice. Always check for revised or updated information. To help avoid personal injury to you or others, and to avoid damage to the vehicle on which you are working, you must always ref er to the latest Mercedes- Benz Technical Publication and follow all pertinent instructions when testing, diagnosing or making repair. Illustrations and descriptions in this training reference are based on preliminary information and may not correspond to the final US version vehicles. Refer to the official introduction manual and WIS when available. Copyright Mercedes-Benz USA, LLC, 2004 WIS document numbers shown apply to WIS Version USA/CDN at date of writing. Reproduction by any means or by any information storage and retrieval system or translation in whole or part is not permitted without written authorization from from Mercedes- Benz USA, LLC or it's successors. Published by Mercedes -Benz USA, LLC Printed in U. S.A.
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Contents Advantages of SBC Driving with SBC
5 8
SBC components
13
Brake operating unit (BOU) Traction system hydraulic unit
17 27
Three pressure stages
32
Temperature Compensation Deactivation
38 39
System activation
42
Bleeding the system
49
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SBC Incorporates these Functions:
ABS (Anti lock Brakes 1984) + ASR (Automatic Slip Regulation 1991) + ETS (Electronic Traction System 1995) + ESP (Electronic Stability Program 1996) + BAS (Brake Assist System 1998)
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Advantages of SBC • Improves Improves metering metering of required required brake brake pressure pressure – each wheel wheel can be precisely precisely controlled controlled • Im Impro prove ved d BAS BAS fun funct ctio ion n – monitors monitors release of accelerato acceleratorr pedal and application application of brake – maximum maximum pressure pressure available available immediat immediately ely – pre-filling pre-filling of system system (overcomi (overcoming ng play) play) – when the BAS function function is anticip anticipated, ated, slight slight pressure pressure is applied
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Advantages of SBC • Electronic Electronic Brake Proportioning: Proportioning: EBP – allows brake brake proportionin proportioning g front to back and side side to side • No pedal vibration vibration during during ABS operation operation – eliminates eliminates “distraction “distraction”” to the driver during critical critical moments – indicator indicator light in instrument instrument cluster cluster signals signals traction traction loss • Improved Improved driving driving dynamics: dynamics: ABS, ASR, ASR, and ESP – faster response to brake brake request request inputs inputs
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Advantages of SBC • Pressure reduction reduction at standstill standstill – reduces reduces stress stress on compone components nts • Dry braki braking ng funct function ion – wiper wiper inpu inputt via via CAN CAN – ~every ~every 7 to 14 minu minutes tes – brake brake actuatio actuation n changes changes time interval
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Driv Drivin ing g with with SBC SBC - Wake-Up Wake-Up SBC is functional as soon as it is “wakened” by: • opening opening a door door (via (via CAN) CAN) • operating the the central locking locking system (via CAN) • depress depressing ing the the brake brake pedal pedal • turning turning key to positi position on 1 • operating operating parking parking brake •The Wake-Up may be followed by a Pre-Drive self Check performed by SBC
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Drivin Driving g with with SBC – Pre-Driv Pre-Drive e Check (PDC) (PDC) When SBC performs a PDC after a "wake-up", the following are checked: Warning! Pressure is applied to brake calipers (~60 bar) • reservoir reservoir pressure pressure (if low, low, it will be be corrected corrected by running the the high pressure charge pump in the hydraulic unit) • pres pressu sure re sens sensor ors s • cont contro roll val valve ves s • leak tests • op oper erat atio iona nall che check cks s Note: self-tests are constantly conducted during driving (~ once every 16 brake applications)
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Drivin Driving g with with SBC – Delayed Delayed Off Off Functio Function n
Time that SBC remains operational after use: • with vehicle vehicle stationary stationary and and was locked locked = 20 seconds • with vehicle vehicle stationa stationary ry and ignition ignition in in “0”, brake pedal not operated = 2 minutes • with vehicle vehicle stationary, stationary, ignition ignition in “0”, brake pedal operated in delayed off phase and released again = 4 minutes 10
Warning Display
Complete ESP control module failure Instrument cluster will scroll through failure displays
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Warning Display SBC control module failure
Certain faults will trigger audible signal
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SBC Components
• Brake Operat Operating ing Unit Unit (BOU) (BOU) • Wheel Wheel speed speed sensor sensors s • Traction Traction System System Hydraulic Hydraulic Unit (A7/3) 13
W211 System Overview Circuit 30
Brake lights
Rear SAM (N10/2)
Circuit 87 SBC
Circuit 31 Wheel speed sensors L6/1, L6/2, L6/3, L6/4
SBC control module (A7/3n1)
CAN Wheel speeds
Wake up
Stop lamp switch (S9/1) SBC pedal travel sensor (B37/1)
Brake lights Speed status Diagnostics
ESP control module (N47/5)
Front SAM (N10/1)
Diagnostic connector (X11/4) 14
R230 System Overview Circuit 30
Brake lights
Circuit 87 Circuit 31 Wheel speed sensors L6/1, L6/2, L6/3, L6/4 Stop lamp switch (S9/1) SBC pedal travel sensor (B37/1)
SBC control module (A7/3n1)
Rear SAM (N10/8)
Diagnostic connector (X11/4) SBC CAN Wheel speeds
Wake up Brake lights Speed status
ESP control module (N47/5)
Passenger side SAM (N10/11) 15
X11/4 Diagnosis Connection R230
W211 A7/3n1 SBC
A7/3n1 SBC
X11/4
N47/5 ESP X11/4
N10/1 L.F.SAM
N15/5 ESM
Z70/4 Pin 9
Z6/33 Pin 9 N51/2 ABC
N47/5 ESP
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Brake Brake Opera Operatin ting g Unit Unit - (BOU) (BOU)
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Brake Operating Unit The Brake Operating Unit (BOU) consists of the following: • Brake Brake fluid fluid reserv reservoir oir (Do not overfill!) • SBC pedal value sensor
• Tandem Tandem master master cylinder cylinder
• Brake pressure pressure simula simulator tor (Note: no vacuum booster)
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Master Cylinder • Fluid Fluid lev level el sens sensor or • Fluid Fluid ret retur urn n line line • Do not not o ove verf rfililll • Hydraulic Hydraulic lines to SBC SBC • Suppl Supply y hose hose to to SBC SBC 19
Fluid Reservoir Cover
• Ultravio Ultraviolet let protecti protection on (211 only)
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Pedal Pedal Value Value Sens Sensor or - (B37/1 (B37/1)) • Contains Contains two hall hall effect effect sensors sensors • Converts Converts pedal pedal travel travel value to to an electrical signal • Provides Provides input input to to SBC SBC control module A7/3
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BOU Tandem Master Cylinder Fluid reservoir Fill valves
Primary piston
Floating piston
y2
y1
A7/3 - Traction Traction system hydraulic hydraulic unit with separation valves y1 and y2
A7/3 Brake pressure simulator
22 GF42.46-P-4200-03SL
Normal Normal Braking Braking - Light Pressure Pressure • Driver applies pressure to the brake pedal • Fill valves valves close close • Pedal Pedal travel travel senso sensorr sends a signal to A7/3 • y1 and y2 y2 energize energized, d, preventing fluid movement externally
y2
y1 A7/3
• Floating Floating pisto piston n allows allows fluid to enter simulator, compressing the light spring, providing pedal feel to the driver 23 GF42.46-P-4200-03SL
Normal Normal Braking Braking - Increased Increased Pressure Pressure
y2
y1 A7/3
• Increa Increasin sing g pedal pedal travel causes the larger spring to compress, providing harder pedal feel 24
Normal Normal Braking Braking - Strongest Strongest Feedback Feedback
• Further pedal travel
y2
y1 A7/3
causes piston to compress rubber bumper, providing greatly increased pedal pressure 25
Emergency Operation • All electrical functions canceled
• Hydraulic pressure created with NO power assist • Pressur Pressure e directe directed d through A7/3 y1 and y2 to .... Left Front and Right Front calipers only !
y2
y1 Left front
A7/3
Right front 26 GF42.46-P-4200-03SL GF42.46-P-3000SL
Traction System Hydraulic Unit (A7/3)
Consists of: • SBC control control module module (A7/3n1 (A7/3n1))
• High pressure charge pump (A7/3m1)
• Pressure Pressure reservoir reservoir
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Traction System Hydraulic Unit A7/3
28 GF42.50-P-4000-03S
Legend 1 2 3 7 8 A7/3 A7/3 A7/3b1 b1 A7/3 A7/3b2 b2 A7/3 A7/3b3 b3 A7/3 A7/3b4 b4 A7/3 A7/3b5 b5 A7/3 A7/3b6 b6 A7/ A7/3m1
Brake Operating Unit Brake pressure simulator Pressure reservoir Left front media separator (dividing piston) Right front media separators (dividing piston) Traction sy system hy hydraulic un unit Fron Frontt axl axle e pre pre-pr -pres essu sure re sens sensor or Rese Re serv rvoi oirr pre press ssur ure e sen senso sorr Left Le ft fron frontt pre press ssur ure e sen senso sorr Righ Rightt fron frontt pres pressu sure re sen senso sorr Left Le ft rear rear pres pressu sure re sens sensor or Righ Rightt rea rearr pre press ssur ure e sen senso sorr High High-pr -pres essu sure re cha charg rge e pu pump mp
A7/3y1 A7/ A7/3y2 3y2 A7/ A7/3y3 3y3 A7/ A7/3y4 3y4 A7/3 A7/3y6 y6 A7/3 A7/3y7 y7 A7/3 A7/3y8 y8 A7/3 A7/3y9 y9 A7/3 A7/3y1 y10 0 A7/3 A7/3y1 y11 1 A7/3 A7/3y1 y12 2 A7/3 A7/3y1 y13 3 B37/1 S9/1
Left front separation valve Righ ight fron frontt sep sepa arati ratio on val valve Fron ontt axl axle ba ballan anc ce val valve Rear axle ba ballance valve Left Le ft fron frontt int intak ake e con contr trol ol valv valve e Left Le ft fron frontt ou outl tlet et cont contro roll valv valve e Righ Rightt fro front nt inta intake ke cont contro roll val valve ve Righ Rightt fro front nt ou outl tlet et cont contro roll val valve ve Left Le ft rea rearr inta intake ke con contr trol ol val valve ve Left Le ft rea rearr outl outlet et con contr trol ol val valve ve Righ Rightt rear rear int intak ake e cont contro roll valv valve e Righ Rightt rear rear out outle lett cont contro roll valv valve e SBC pedal value sensor Stop lamp switch (4- pin)
29
Emergency Operation Circuit
• Pressure Pressure applied applied directly directly to front calipers • y1 and and y2 not not ene energize rgized d • b1, b3, b3, and b4 b4 pressure pressure sensors may provide information to SBC control module • Media separator/Di separator/Dividing viding piston 7 and 8 isolate emergency circuit from normal circuit
30 GF42.46-P3000SL
Brake Pressure Supply
• pressure pressure reservoir reservoir charged charged to 160 bar • the high high pressure pressure charge charge pump pump runs as needed • pressure blocked by y6, y8, y10, y12
31 GF 42.50-P-4000-04S GF42.46-P-0001SL
Three Pressure Stages
Same pressure stages as used with ABS functions: • Pres Pressu sure re appl apply y • Pres Pressu sure re hol hold d • Pressu Pressure re release release
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Pressu Pressure re Apply Apply - Rear Wheels Wheels
Brake pedal pressure Reservoir pressure
• Brake Brake ped pedal al d depres epressed sed • B37/1 and b1 report brake application to control module • y1 and and y2 energ energize ized d • y10 and y12 intake intake control control valves valves energized • Pressure Pressure at each each rear rear wheel monitored by b5 and b6 • Balance Balance valve valve y4 not energiz energized ed
GF42.50-P-4000-04S33 GF42.46-P-1000SL GF42.46-P-4500-02SL
Pressu Pressure re Apply Apply - Front Front Whee Wheels ls
Brake pedal pressure Reservoir pressure
• y6 and and y8 y8 energiz energized ed • pressure pressure applied applied to left left an and d right dividing pistons 7 and 8 • 7 and 8 apply apply pressure pressure to caliper caliper • pressure pressure at each wheel wheel monitore monitored d by b3 and b4 • Balance Balance valve valve y3 not energi energized zed 34 GF42.50-P-4000-04S GF42.46-P-1000SL
Pressu Pressure re Apply Apply - All Whee Wheels ls
• Outlet control control valves y7, y9, y11, y11, y13 energized energized
35 GF42.50-P-4000-04S GF42.46-P-1000SL
Pressu Pressure re Hold Hold - All Wheels Wheels • y6, y8, y10, y10, y12 de-ener de-energized gized
36 GF42.50-P-4000-04S GF42.46-P-1000SL
Pressure Pressure Reduct Reduction ion - All Wheels Wheels • y7, y9, y11, y13 y13 de-ener de-energize gized d
37 GF42.50-P-4000-04S GF42.46-P-1000SL
Temperature Compensation
During continuous brake use the fluid in the calipers expand, this: • creates creates high high pressure pressure • prevents prevents valves valves 7 & 8 from movin moving g To reduce this pressure, y1 and y2 are pulsed 38
Deactivation SBC must be deactivated with SDS before any work is performed on the system. This will prevent the pre-drive check from being automatically performed which could cause injury.
Deactivating the system will: • empty empty the pressure pressure reserv reservoir oir (a lower pressure with no volume may be retained) • prevent prevent the charge charge pump pump from operatin operating g •Note: the warning buzzer is deactivated when accessing SBC with the SDS. 39
Deactivation SBC must be deactivated PRIOR to: to: • working working on the hydraul hydraulic ic system system • removing removing or install installing ing brake brake pads • replaci replacing ng rotors rotors • replacing replacing the pressure reservoir reservoir • replacin replacing g the the BOU • replacing replacing the SBC SBC hydraulic hydraulic unit (A7/3) (A7/3) 40
Deactivation Charge pump disabled and accumulator fluid returned to the reservoir!
41
Pressure at A7/3b2
System Activation Activation must be performed anytime the system has been deactivated, BEFORE the engine is started! Failure to activate will prevent proper operation and create fault codes! Activating SBC with SDS will: • charge charge the the accumul accumulator ator • perform perform a Predri Predrive ve Check Check • move the pads pads towards towards the rotors rotors with ~60 bar pressur pressure e • erase the fault fault memory memory (Note: may have to activate several times to position the brake pads)
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System Activation
43
Activa Activati tion on - Lef Leftt Front Front
Caliper held with ~60 bar
44
Activa Activati tion on - Right Right Front Front
Caliper held with ~60 bar
45
Activ Activati ation on - Right Rear
Caliper held with ~60 bar
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Activa Activati tion on - Left Rear
Caliper held with ~60 bar
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Activa Activati tion on - Recharg Recharge e
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Bleeding the Brake System
Proper system bleeding is critical! Follow directions in SDS • Bleeding must be performed using the SDS
• Pressure Pressure at bleeder bleeder valves will will exceed exceed 100 bar (Hold the bleeder hose securely) • Bleeding Bleeding may require require ~1.5 hours • Bleeding Bleeding may use use ~ 1.5 liters liters of brake fluid fluid 49 AR42.10-P-0012R
Equipment Required • Pres Pressu sure re bleed bleeder er • Adap Adapte ters rs • Fluid Fluid recept receptacl acle e • SD SDS S - follow follow instru instructi ctions ons carefu carefully lly 211 589 01 91 00
CAUTION: Extremely high pressure at bleeder! AR42.10-P-0010-02R AR42.10-P-0012R WS42.00-P-0048B
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Bleeding the Brake System Connect equipment and follow steps in SDS
51 AR42.10-P-0012R
Acronym List (Used in This Handout.)
ABS ABS - Anti-lock Anti-lock Brak Brake e System System ASR ASR - Anti Slip Regu Regulatio lation n BAS BAS - Brake Brake Assist Assist System System BOU - Brake Brake Operati Operating ng Unit Unit CAN - Controller Controller Area Netwo Network rk EBP EBP - Electronic Electronic Brake Brake Proporti Proportioning oning EBR EBR - Electroni Electronic c Brake Brake Regulation Regulation E-Gas E-Gas - Electron Electronic ic Accelera Accelerator tor ESP ESP - Electron Electronic ic Stability Stability Progra Program m ETS ETS - Electron Electronic ic Traction Traction System System PDC PD C - Predr Predrive ive Che Check ck SAM SAM - Signal Signal Acquisi Acquisition tion Module Module SBC SBC - Sensotron Sensotronic ic Brake Brake Control Control
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Appendix
AR42.10-P-0010I AR42.10-P-0012R GF42.45-P-0001-04SL GF42.45-P-0001-04SL GF42.45-P-0001SL GF42.45-P-0001SL GF42.45-P-2000SL GF42.45-P-2000SL GF42.45-P-3500SL GF42.45-P-3500SL GF42.46-P-0001SL GF42.46-P-0001SL GF42.46-P-1000SL GF42.46-P-1000SL GF42.46-P-2000SL GF42.46-P-2000SL GF42.46-P-3000SL GF42.46-P-3000SL GF42.46-P-4200-03SL GF42.46-P-4200-03SL GF42.46-P-4210SL GF42.46-P-4210SL GF42.46-P-4500-02SL GF42.46-P-4500-02SL GF42.50-P-4000-03S GF42.50-P-4000-04S GF42.50-P-4000S WS42.00-P-0048B WS42.00-P-0048B
Carrying out bleeding operation Bleeding system with Star Diagnosis ESP driver information ESP function ESP brake moment control ASR control mode function SBC function SBC Normal braking function SBC additional braking functions SBC braking with malfunction BOU function SBC pedal value sensor SBC control module – task Hydraulic unit design Hydraulic unit function Hydraulic unit task/location/function EHB adaptor
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