Overall network
Networking
75
Introduction of the New A-Class, Model Series 176
b
Introduction
The ever increasing demands on the on-board elec-
tronic system in the fields of vehicle safety,
comfort, communications and diagnosis require
wider and wider networking of the existing systems
in order to allow the necessary information to be
exchanged. To create a complete vehicle network,
some control units act as a gateway i.e. data from
the connected bus systems are routed by these
control units.
The following data bus systems are used to
exchange the necessary information:
• Controller Area Network (CAN)
• Media Oriented System Transport (MOST)
CAN overview
The following CAN buses are involved in the overall
network:
•
Telematics CAN (CAN A)
Transfer rate 125 kBit/s.
•
Interior CAN (CAN B)
Transfer rate 125 kBit/s.
•
Drivetrain CAN (CAN C)
Transfer rate 500 kBit/s.
•
Diagnostic CAN (CAN D)
Transfer rate 500 kBit/s.
•
Chassis CAN (CAN E)
Transfer rate 500 kBit/s.
•
Front end CAN (CAN G)
Transfer rate 500 kBit/s.
•
Drivetrain sensor CAN (CAN I)
Transfer rate 500 kBit/s.
•
Drivetrain CAN (CAN T)
Transfer rate 500 kBit/s.
Gateway function
Control units with a gateway function can receive
signals from more than one data bus and also relay
signals via these particular data bus systems as
they are linked with two or more data bus systems.
This control units include:
• ME-SFI [ME] control unit
• CDI control unit
• EZS control unit
• COMAND
Electronic ignition lock (EZS) control unit
with central gateway function
The gateway is integrated in the EZS and links the
following bus systems to each other:
• Diagnostic CAN (CAN D)
• Interior CAN (CAN B)
• Chassis CAN (CAN E)
• Front end CAN (CAN G)
Fuses
Maxi and ATO fuses are used as well as, for the first
time, mini fuses. They are located in the following
positions on the vehicle so that they are accessible
to the customer:
• In the front fuse and relay box (SRB) in the
engine compartment
• In the front passenger footwell
Prefuses 1 to 8 and the decoupling relay for the
ECO start/stop function are located in the prefuse
box on the left of the engine compartment. The
pyrofuse is located on the on-board electrical
system battery on the left of the engine compart-
ment. This disconnects the starter and alternator
line from the battery in the event of a crash.
– This printout will not be recorded by the update service. Status: 06 / 2012 –
