Mercedes-Benz W211 manual

1 Sensotronic Brake Control (SBC) 327 HO 09 SBC (WJB) 03 - 05 - 04 R230 and W211: Starting MY2003[...]

2 Objectives At the end of this presentation, you should be able to: 1. Explain the function of and purpose for SBC 2. Describe the customer interface with SBC 3. List the hydraulic and electronic components used for SBC 4. Describe how the “normal” feel of the brake pedal is maintained 5. Explain emergency operation of the SBC braking system 6[...]

3 Contents Advantages of SBC 5 Driving with SBC 8 SBC components 13 Brake operating unit (BOU) 17 Traction system hydraulic unit 27 Three pressure stages 32 Temperature Compensation 38 Deactivation 39 System activation 42 Bleeding the system 49[...]

4 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)[...]

5 Advantages of SBC • Improves metering of required brake pressure – each wheel can be precisely controlled • Improved BAS function – monitors release of accelerator pedal and application of brake – maximum pressure available immediately – pre - filling of system (overcoming play) – when the BAS function is anticipated, slight pressur[...]

6 Advantages of SBC • Electronic Brake Proportioning: EBP – allows brake proportioning front to back and side to side • No pedal vibration during ABS operation – eliminates “distraction” to the driver during critical moments – indicator light in instrument cluster signals traction loss • Improved driving dynamics: ABS, ASR, and ESP [...]

7 Advantages of SBC • Pressure reduction at standstill – reduces stress on components • Dry braking function – wiper input via CAN – ~every 7 to 14 minutes – brake actuation changes time interval[...]

8 Driving with SBC - Wake - Up SBC is functional as soon as it is “wakened” by: • opening a door (via CAN) • operating the central locking system (via CAN) • depressing the brake pedal • turning key to position 1 • operating parking brake • The Wake - Up may be followed by a Pre - Drive self Check performed by SBC[...]

9 Driving with SBC – Pre - Drive Check (PDC) When SBC performs a PDC after a "wake - up", the following are checked: Warning! Pressure is applied to brake calipers (~60 bar) • reservoir pressure (if low, it will be corrected by running th e high pressure charge pump in the hydraulic unit) • pressure sensors • control valves • le[...]

10 Driving with SBC – Delayed Off Function Time that SBC remains operational after use: • with vehicle stationary and was locked = 20 seconds • with vehicle stationary and ignition in “0”, brake pedal not operated = 2 minutes • with vehicle stationary, ignition in “0”, brake pedal operated in delayed off phase and released again = 4[...]

11 Warning Display Complete ESP control module failure - Instrument cluster will scroll through failure displays[...]

12 Warning Display SBC control module failure Certain faults will trigger audible signal[...]

13 SBC Components • Brake Operating Unit (BOU) • Wheel speed sensors • Traction System Hydraulic Unit (A7/3)[...]

14 W211 System Overview SBC control module (A7/3n1) Circuit 30 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) Rear SAM (N10/2) ESP control module (N47/5) Front SAM (N10/1) SBC CAN Wheel speeds Wake up Brake lights Speed status Brake lights Diagnostics Diagnostic connector (X1[...]

15 R230 System Overview SBC control module (A7/3n1) Circuit 30 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) Diagnostic connector (X11/4) Rear SAM (N10/8) ESP control module (N47/5) SBC CAN Wheel speeds Brake lights Passenger side SAM (N10/11) Wake up Brake lights Speed stat[...]

16 X11/4 Diagnosis Connection X11/4 Pin 9 Z6/33 R230 W211 A7/3n1 SBC N47/5 ESP N15/5 ESM N51/2 ABC X11/4 Pin 9 A7/3n1 SBC N47/5 ESP Z70/4 N10/1 L.F.SAM[...]

17 Brake Operating Unit - (BOU)[...]

18 Brake Operating Unit The Brake Operating Unit (BOU) consists of the following: • Brake fluid reservoir (Do not overfill!) • SBC pedal value sensor • Tandem master cylinder • Brake pressure simulator (Note: no vacuum booster)[...]

19 Master Cylinder • Fluid return line • Supply hose to SBC • Do not overfill • Fluid level sensor • Hydraulic lines to SBC[...]

20 Fluid Reservoir Cover • Ultraviolet protection (211 only)[...]

21 Pedal Value Sensor - (B37/1) • Contains two hall effect sensors • Converts pedal travel value to an electrical signal • Provides input to SBC control module A7/3[...]

22 BOU Tandem Master Cylinder Fluid reservoir Floating piston Primary piston Brake pressure simulator Fill valves GF42.46 - P - 4200 - 03SL A7/3 y1 y2 A7/3 - Traction system hydraulic unit with separation valves y1 and y2[...]

23 Normal Braking - Light Pressure A7/3 y1 y2 GF42.46 - P - 4200 - 03SL • Driver applies pressure to the brake pedal • Pedal travel sensor sends a signal to A7/3 • Fill valves close • y1 and y2 energized, preventing fluid movement externally • Floating piston allows fluid to enter simulator, compressing the light spring, providing pedal f[...]

24 Normal Braking - Increased Pressure A7/3 y1 y2 • Increasing pedal travel causes the larger spring to compress, providing harder pedal feel[...]

25 Normal Braking - Strongest Feedback A7/3 y1 y2 • Further pedal travel causes piston to compress rubber bumper, providing greatly increased pedal pressure[...]

26 Emergency Operation A7/3 y1 y2 Left front Right front GF42.46 - P - 4200 - 03SL GF42.46 - P - 3000SL • All electrical functions canceled • Hydraulic pressure created with NO power assist • Pressure directed through A7/3 y1 and y2 to .... Left Front and Right Front calipers only ![...]

27 Traction System Hydraulic Unit (A7/3) Consists of: • SBC control module (A7/3n1) • High pressure charge pump (A7/3m1) • Pressure reservoir[...]

28 Traction System Hydraulic Unit A7/3 GF42.50 - P - 4000 - 03S[...]

29 Legend 1 Brake Operating Unit 2 Brake pressure simulator 3 Pressure reservoir 7 Left front media separator (dividing piston) 8 Right front media separators (dividing piston) A7/3 Traction system hydraulic unit A7/3b1 Front axle pre - pressure sensor A7/3b2 Reservoir pressure sensor A7/3b3 Left front pressure sensor A7/3b4 Right front pressure se[...]

30 Emergency Operation Circuit GF42.46 - P3000SL • Pressure applied directly to front calipers • y1 and y2 not energized • b1, b3, and b4 pressure sensors may provide information to SBC control module • Media separator/Dividing piston 7 and 8 isolate emergency circuit from normal circuit[...]

31 Brake Pressure Supply GF 42.50 - P - 4000 - 04S GF42.46 - P - 0001SL • pressure reservoir charged to 160 bar • the high pressure charge pump runs as needed • pressure blocked by y6, y8, y10, y12[...]

32 Three Pressure Stages Same pressure stages as used with ABS functions: • Pressure apply • Pressure hold • Pressure release[...]

33 Pressure Apply - Rear Wheels GF42.50 - P - 4000 - 04S GF42.46 - P - 1000SL GF42.46 - P - 4500 - 02SL Reservoir pressure Brake pedal pressure • Brake pedal depressed • B37/1 and b1 report brake application to control module • y1 and y2 energized • y10 and y12 intake control valves energized • Pressure at each rear wheel monitored by b5 [...]

34 Pressure Apply - Front Wheels GF42.50 - P - 4000 - 04S GF42.46 - P - 1000SL Reservoir pressure Brake pedal pressure • y6 and y8 energized • pressure applied to left and right dividing pistons 7 and 8 • 7 and 8 apply pressure to caliper • pressure at each wheel monitored by b3 and b4 • Balance valve y3 not energized[...]

35 Pressure Apply - All Wheels GF42.50 - P - 4000 - 04S GF42.46 - P - 1000SL • Outlet control valves y7, y9, y11, y13 energized[...]

36 Pressure Hold - All Wheels GF42.50 - P - 4000 - 04S GF42.46 - P - 1000SL • y6, y8, y10, y12 de - energized[...]

37 Pressure Reduction - All Wheels GF42.50 - P - 4000 - 04S GF42.46 - P - 1000SL • y7, y9, y11, y13 de - energized[...]

38 Temperature Compensation During continuous brake use the fluid in the calipers expand, this: • creates high pressure • prevents valves 7 & 8 from moving To reduce this pressure, y1 and y2 are pulsed[...]

39 Deactivation Deactivating the system will: • empty the pressure reservoir (a lower pressure with no volume may be retained) • prevent the charge pump from operating • Note: the warning buzzer is deactivated when accessing SBC with the SDS. SBC must be deactivated with SDS before any work is performed on the system. This will prevent the pr[...]

40 Deactivation SBC must be deactivated PRIOR to: • working on the hydraulic system • removing or installing brake pads • replacing rotors • replacing the pressure reservoir • replacing the BOU • replacing the SBC hydraulic unit (A7/3)[...]

41 Deactivation Charge pump disabled and accumulator fluid returned to the reser voir! Pressure at A7/3b2[...]

42 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 fau lt codes! Activating SBC with SDS will: • charge the accumulator • perform a Predrive Check • move the pads towards the rotors with ~60 bar pressure • erase[...]

43 System Activation[...]

44 Activation - Left Front Caliper held with ~60 bar[...]

45 Activation - Right Front Caliper held with ~60 bar[...]

46 Activation - Right Rear Caliper held with ~60 bar[...]

47 Activation - Left Rear Caliper held with ~60 bar[...]

48 Activation - Recharge[...]

49 Bleeding the Brake System Proper system bleeding is critical! Follow directions in SDS • Bleeding must be performed using the SDS • Pressure at bleeder valves will exceed 100 bar (Hold the bleeder hose securely) • Bleeding may require ~1.5 hours • Bleeding may use ~ 1.5 liters of brake fluid AR42.10 - P - 0012R[...]

50 Equipment Required • Pressure bleeder • Adapters • Fluid receptacle • SDS - follow instructions carefully CAUTION: Extremely high pressure at bleeder! 211 589 01 91 00 AR42.10 - P - 0010 - 02R AR42.10 - P - 0012R WS42.00 - P - 0048B[...]

51 Bleeding the Brake System AR42.10 - P - 0012R Connect equipment and follow steps in SDS[...]

52 Acronym List (Used in This Handout.) ABS - Anti - lock Brake System ASR - Anti Slip Regulation BAS - Brake Assist System BOU - Brake Operating Unit CAN - Controller Area Network EBP - Electronic Brake Proportioning EBR - Electronic Brake Regulation E - Gas - Electronic Accelerator ESP - Electronic Stability Program ETS - Electronic Traction Syst[...]

53 Appendix AR42.10 - P - 0010I Carrying out bleeding operation AR42.10 - P - 0012R Bleeding system with Star Diagnosis GF42.45 - P - 0001 - 04SL ESP driver information GF42.45 - P - 0001SL ESP function GF42.45 - P - 2000SL ESP brake moment co ntrol GF42.45 - P - 3500SL ASR control mode function GF42.46 - P - 0001SL SBC function GF42.46 - P - 1000S[...]