Networking
78
Body
Introduction of the New GLK-Class (USA), Introduction into Service Manual for Model Series 204
v
Network architecture
On recent systems, one of the characteristics of the
network topology for electronic control units is the
division of the network into two subnetworks (engine
CAN Class C and interior CAN Class B) which are
linked to each other via the electronic ignition lock
(EZS). In addition, a gateway function integrated in the
head unit connects the MOST (Media Oriented System
Transport) telematics network to the interior bus.
The most important differences to the previous
network architecture include:
• Linking of the CAN subnetworks via several control
units with integral gateway functions
• Use of numerous subbus systems in the form of
single-wire buses (LIN for Local Interconnect
Network).
Diagnostic CAN
On the GLK-Class, the diagnostic CAN is the sole diag-
nosis communications interface between the external
diagnosis test system and the vehicle. It offers the
benefits of a high data transfer rate (500 kB)
combined with the ability to diagnose control units
simultaneously. The vehicle thus meets the legal
requirements for exhaust gas diagnosis.
All CAN and MOST control units have diagnosis capa-
bility. LIN components are diagnosed through their
associated master control units. Each control unit has
its own internal fault memory.
Electrical wiring harnesses and fuses
The wiring harnesses for the interior compartment,
cockpit and engine compartment are designed
customer-specifically. The wiring harness variants
result from the basic standard equipment, the engine
type, special equipment and national versions.
The wiring harnesses in the interior compartment are
routed through the frame floor system in a H-shape
and are protected by cable ducts in critical areas.
The vehicle fuses are accessible at the following
points:
• Front SRB (engine compartment) and rear SRB
(trunk)
• Cockpit fuse box (outer left) depending on
equipment
i
Note
The prefuse box contains a pyrofuse that isolates
the starter and alternator lines from the battery in
the event of an accident.
