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Front SAM control unit with fuse and relay module, component description - GF54.21-P-6070CE

WARNING: This page is about a different car, the 2011 Mercedes-Benz C300, 2010 Mercedes-Benz C300, 2009 Mercedes-Benz C300, and 2008 Mercedes-Benz C300. However, it is still accessible from the selected car via links, so may be relevant.

MODEL 204.0 /2 as of model year 2009 /YoM 08 

MODEL 204.3 

MODEL 204.9 

Fig 1: Identifying Front SAM Control Unit With Fuse And Relay Module
G07673839Courtesy of MERCEDES-BENZ USA

Task 

Located in the front SAM control unit are two microprocessors, one for control of basic functions, e.g. the exterior lights (ABL) and the second for control of the central gateway functions. Both processors communicate internally with each other over the interior CAN (CAN B) and they can undergo separate diagnosis. The front SAM control unit also has an acceleration sensor integrated into it, which is used to detect any crash events.

IMPORTANT With model 204.9, driving at swift speeds on uneven roads can result in the acceleration sensors being activated because of powerful vibrations. These are entered into an event memory. When mounting, make sure that the front SAM control unit is securely seated.

The processor is responsible for the following tasks for controlling the central gateway functions:

The processor is responsible for the following tasks for controlling the basic functions:

The fuse and relay module of the front SAM control unit supplies various systems and control units with power through limit switches to match the function sequence.

The following tasks are the responsibility of the fuse and relay module:

IMPORTANT Detailed information is available in the "Fuse and relay box, as-built configuration" function description.

Central gateway (CAN interface) 

The processor for controlling the central gateway functions also acts as an interface between the following databus systems:

Data container 

The data container represents a nonvolatile, mobile data memory and is managed by the processor for controlling the central gateway functions.

Benefits: During production, vehicle-specific, test location-specific and control unit-specific data are stored in the data container (e.g. production number, test status, partial tests not completed). These data can be used in the subsequent tests for test sequence control. The total size of the data memory is 128 bytes.

System diagnosis 

The system diagnosis is integrated as a software module in the processor for controlling central gateway functions.

For off-board diagnosis, the following on-board functions are realized by the processor responsible for controlling the central gateway functions:

Global variant coding 

The processor responsible for controlling the central gateway functions forwards global information such as model series and national version over the various CAN buses to the networked control units. The control units perform part of their configuration process to match this information.

Monitoring CAN bus idle 

The monitoring of the CAN bus idle enables control units to be determined, which keep the CAN bus active at what otherwise is expected to be a CAN bus idle period.

This information is filed in a nonvolatile memory. This in turn serves to ensure that even when the on-board electrical system battery (G1) has been discharged and following a reset of the networked control units, it is still possible to determine whether the discharging of the on-board electrical system battery was caused by the network or by an individual CAN user.

Interior CAN and LIN interface 

The processor for controlling the basic functions also acts as an interface between the following databus systems:

Reading in of sensors, pickups and signals 

The input factors are read in via the following connections:

Direct line 

The signals from the following components are read via a direct line:

Instrument panel LIN 

The signals from the following components are read-in over the instrument panel LIN:

Wiper/inside rearview mirror LIN 

The signals of the following components are read in via the wiper LIN:

IMPORTANT The communication with the processor responsible for controlling the central gateway functions can also send the data read in by the processor responsible for controlling the basic functions to control units that are not connected to the interior CAN.

CAN 

The processor responsible for controlling the basic functions reads in function-relevant data over the interior CAN.

Information from control units that are not connected to the interior CAN are sent by the processor responsible for controlling the central gateway functions over the interior CAN. This can be information from control units, which are connected to one of the following CANs:

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Evaluation of input factors 

The input factors are evaluated by the processor responsible for controlling the basic functions whereupon the corresponding components are then actuated.

Controlling functions 

The processor responsible for controlling the basic functions manages the following functions:

Actuation of components 

Components are actuated via the following lines:

Direct line 

The following components are actuated over a direct line by the processor responsible for controlling the basic functions:

Instrument panel LIN 

The following components are actuated via the instrument panel LIN:

Wiper/inside rearview mirror LIN 

The following components are actuated via the wiper LIN:

REFER TO SYSTEM WIRING DIAGRAMS Wiring diagram of front SAM control unit with fuse and relay module (N10/1) Sheet 1 PE54.21-P-2106-97FAA
Sheet 2 PE54.21-P-2106-97FAB
Sheet 3 PE54.21-P-2106-97FAC
Sheet 4 PE54.21-P-2106-97FAD
Sheet 5 PE54.21-P-2106-97FAE
Sheet 6 PE54.21-P-2106-97FAF
Sheet 7 PE54.21-P-2106-97FAG
Sheet 8 PE54.21-P-2106-97FAH
Sheet 9 PE54.21-P-2106-97FAI
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