Ver. 06.09.08
1. General information.
Mercedes Benz were one of the first vehicle manufacturers to employ a brake-by-wire
system on a car (W211, R230). Called sensotronic (SBC), the system no longer relies on the
driver to produce hydraulic pressure. The brake pedal is connected to the computer (ECU) by
wire (brake-by-wire). The sensors on the brake pedal will inform the computer how the pedal
is pressed, eg how far, how fast etc. The computer will then dissipate the required force to
each wheel via modulators.
2. SBC - Traction System Hydraulic Unit (A7/3) structure.
SBC control module (A7/3n1)
High pressure charge pump
(A7/3m1)
Pressure reservoir
3. SBC durability.
The SBC module counts breaking cycles, after exciting the value of 300000, an error
message occurs. It's a kind of protection for the mechanical parts eg. motor, inside the traction
system hydraulic unit (A7/3). The contents of the message and the value of cycle limiter
differs  software depending. It can be for example:  SBC defekt, sofort Händler aufsuchen".
1
W211 ABS/SBC reader set
Ver. 06.09.08
System diagnosis will deliver the following information:
OPERATING TIME OF COMPONENT A7/3 IS EXCEEDED (SBC HYDRAULIC UNIT) -
FAULT CODE C249F
This kind of error can be fixed using the W211 ABS/SBC reader set.
4. W211 ABS/SBC reader set.
W211 ABS/SBC reader set consists of:
- T-Box hardware with special firmware
- Type 2 cable with clamps and connecting probes
5. W211 ABS/SBC reader set configuration.
Programming voltage regulation
- Use voltage control poti and set exact 2,8V. You can control the voltage on
measurement connector - goldpin (see picture below).
- ICP MODE jumper must be in ON position.
- ICVL jumper must be in OFF position (removed).
USB uWire
Ext. Power
F 1
V Prog.
Busy
Run
Mode 1
I2C
F 2
Mode 2
VOLTAGE
ICP MODE
CONTROLL
ON
2,8V
SPI
ICVL
2,5V 5,1V
2
W211 ABS/SBC reader set
Ver. 06.09.08
Software configuration
- Install T-Box hardware and software. For details refer to the T-Box USB installation
document.
- Run W211 SBC software and select Cable Type 2 option (see picture below).
6. Working with W211 ABS/SBC reader set.
SBC must be deactivated with diagnostic tester 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 the pressure reservoir (a lower pressure with no volume may be retained)
" prevent the charge pump from operating
The reader tool requires opening the SBC module. You have to solder the Vcc, connect the
ground with a clamp and connect data lines to the pcb with delivered probes (2 pcs). The
point's are easy to find and connect  see help pictures. After this start the software, set the
delay time and press auto repair button. The software will decrement the delay counter and
after reaching the value of 0 start the sniffing routine. T-Box will try link with the SBC and
modify the SBC memory contents so the error message will disappear.
1. Remove the SBC control module from the car (4 screws )
2. Open the control module cover
3. Connect T-Box with PC and power supply.
4. Connect SBC module Vcc and GND (black clamp for GND, solder Vcc
line)
5. Connect Type 2 adapter with T-Box.
6. Start the software, set the delay time and press AUTO REPAIR
7. Connect data link points, use the delivered probes.
8. Wait for the software to complete the operation.
3
W211 ABS/SBC reader set
Ver. 06.09.08
4
W211 ABS/SBC reader set