Sensotronic Brake Control
(SBC)
1
R230 and W211: Starting MY2003
327 HO 09 SBC (WJB) 03-05-04
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.Describe “temperature compensation”
7.Explain “Deactivation” and describe when it is necessary to do it
8.“Activate” the SBC system
9.Locate tools and the proper procedure for bleeding 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 2 |
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 Mercedes -Benz USA, LLC or it's successors. Published by Mercedes -Benz USA, LLC Printed in U. S.A.
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 |
3
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)
4
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 pressure is applied
5
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
–faster response to brake request inputs
6
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
7
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 |
8 |
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 the high pressure charge pump in the hydraulic unit)
•pressure sensors
•control valves
•leak tests
•operational checks
Note: self-tests are constantly conducted during driving (~ once every 16
brake applications) |
9 |
|
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 minutes
10
Warning Display
Complete ESP control module failure -
Instrument cluster will scroll through failure displays
11
Warning Display
SBC control module failure
Certain faults will trigger audible signal |
12 |
SBC Components
•Brake Operating Unit (BOU)
•Wheel speed sensors
•Traction System Hydraulic Unit (A7/3)
13
W211 System Overview
Circuit 30 |
|
Brake lights |
Rear SAM |
Circuit 87 |
|
|
(N10/2) |
|
SBC |
|
|
|
|
|
|
Circuit 31 |
SBC |
CAN |
ESP control |
Wheel speed sensors |
control |
Wheel |
module (N47/5) |
module |
speeds |
|
|
|
|
||
L6/1, L6/2, L6/3, L6/4 |
(A7/3n1) |
Wake up |
|
|
|
Front |
|
Stop lamp switch |
|
Brake lights |
|
|
Speed status |
SAM |
|
(S9/1) |
|
Diagnostics |
(N10/1) |
SBC pedal travel |
|
Diagnostic connector |
|
sensor (B37/1) |
|
||
|
|
(X11/4) |
|
|
|
|
14
R230 System Overview
Circuit 30 |
|
Brake lights |
Rear SAM |
|
|
(N10/8) |
|
Circuit 87 |
|
|
|
|
|
|
|
Circuit 31 |
SBC |
Diagnostic connector |
|
|
(X11/4) |
||
|
control |
|
|
Wheel speed sensors |
|
|
|
module |
SBC |
|
|
L6/1, L6/2, L6/3, L6/4 |
(A7/3n1) |
CAN |
ESP control |
|
|||
Stop lamp switch |
|
Wheel |
module (N47/5) |
|
speeds |
|
|
(S9/1) |
|
|
|
SBC pedal travel |
|
Wake up |
Passenger side |
|
Brake lights |
||
sensor (B37/1) |
|
Speed status |
SAM (N10/11) |
15
X11/4 Diagnosis Connection
R230 |
|
W211 |
A7/3n1 |
|
A7/3n1 |
|
SBC |
|
SBC |
|
|
|
|
|
N47/5 |
|
X11/4 |
ESP |
|
N10/1 |
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|
|
|
X11/4 |
L.F.SAM |
|
Z70/4 |
|
|
|
|
N15/5 |
|
Pin 9 |
ESM |
|
|
Z6/33 |
|
|
|
Pin 9 |
N47/5 |
N51/2 |
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|
|
ESP |
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ABC |
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16