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Home >> Mercedes Benz >> 2012 >> CLS 550 (218.373) V8-4.6L Turbo (278.922) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Relays and Modules - Computers and Control Systems >> Body Control Module >> Description and Operation >> GF54.21-P-6070FQ Front SAM Control Unit With Fuse and Relay Module, Component Description

GF54.21-P-6070FQ Front SAM Control Unit With Fuse and Relay Module, Component Description




GF54.21-P-6070FQ Front SAM Control Unit With Fuse and Relay Module, Component Description
MODEL 218





N10/1 Front SAM control unit with fuse and relay module

Location
The front SAM control unit is located in the left front of the engine compartment.

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.
The processor for controlling the central gateway-functions has the following tasks:
^ Central gateway (Controller Area Network (CAN) interface)
^ Data container
^ System diagnosis
^ Global variant coding
^ Monitoring of the CAN bus idle
The processor responsible for controlling the basic functions has the following tasks:
^ Interior CAN and local interconnect network (LIN) interface
^ Reading in of sensors, pickups and signals
^ Evaluation of input factors
^ Controlling functions
^ Actuation of components
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:
^ Voltage supply to components
^ Power supply and relay switching
^ Switching consumers using relays
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:
- Interior CAN
- Diagnostic CAN (CAN D)
- Chassis CAN (CAN E)
- Front end CAN (CAN G)

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:
- CAN line diagnosis
- CAN SPECIFIED/ACTUAL configuration
- Data logger for telediagnosis

Global variant coding
The processor responsible for controlling the central gateway functions sends 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:
- Instrument panel LIN (LIN 1)
- Wiper/inside rearview mirror LIN (LIN 2)
- Interior CAN

Reading in of sensors, pickups and signals
The input factors are read in via the following connections:
^ Direct line
^ Instrument panel LIN
^ Wiper/inside rearview mirror LIN
^ CAN

Direct line
The processor for controlling the basic functions reads in the signals from the following components over a direct line:
- Refrigerant pressure sensor (B12)
- Outside temperature sensor (B14)
- Interior lamp automatic function switch (N70/3s3) (without code (414) Power glass tilting/sliding roof)
- Exterior lights switch (S1)
- Right front brake wear sensor (S10/2)
- Right rear brake wear sensor (S10/4)
- Brake fluid level switch (S11)
- Parking brake indicator switch (S12)
- Coolant level switch (S41)
- Windshield washer system fluid level switch (S42)
- Right engine hood contact switch (S62/42) (with code (B03) ECO start/stop function)

Instrument panel LIN
The processor for controlling the basic functions reads in the signals from the following components over an instrument panel LIN:
- Analog clock (A70/1)
- Upper control panel control unit (N72/1)
- Transmission mode button for automatic transmission (S16/12)
- Chassis button group (S77) (with code (488) Steel/air suspension or code (489) AIRmatic (air suspension with continuously adjustable damping))

Wiper/inside rearview mirror LIN
The processor responsible for controlling the basic functions reads in the signals from the following components over a wiper/inside rearview mirror LIN:
- Forward mirror dimming light sensor (A67h1)
- Rearward dimming mirror light sensor (A67h2)
- Garage door opener (A67n2) (with code (231) Garage door opener or code (232) Garage door opener with frequency 284-390 MHz)
- Rain/light sensor (B38/2)
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:
- Chassis CAN
- Diagnostic CAN
- Front end CAN
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:
- ABL
- Interior illumination (IBL)
- Wiper system (WSA)
- Windshield washer heater (with code (875) Heated windscreen washing system)
- Central locking (CL [ZV])
- Headlamp cleaning system
- Decouple on-board electrical system battery and activate additional battery for ECO start/stop function (G1/13) (with code (B03) ECO start/stop function)

Actuation of components
Components are actuated via the following lines:
^ Direct line
^ Instrument panel LIN
^ Wiper/inside rearview mirror LIN

Direct line
The following components are actuated over a direct line by the processor responsible for controlling the basic functions:
- Refrigerant compressor (A9)
- Left front lamp unit (E1)
- Left daytime running lights headlamp (E1/3)
- Right front lamp unit (E2)
- Right daytime running lights headlamp (E2/3)
- Additional with code (460) Canada version or code (494) USA version:
- Left front side marker lamp (E6/1)
- Right front side marker lamp (E6/2)
- Glove compartment lamp (E13/1)
- Right front footwell lamp (E17/15)
- Left front footwell lamp (E17/16)
- Left rear footwell lamp (E17/17)
- Right rear footwell lamp (E17/18)
- Also for code (877) Ambiance illumination:
- Center console ambiance illumination (E43/6)
- Driver instrument panel ambiance illumination (E43/7)
- Front passenger instrument panel ambiance illumination (E43/8)
- Left fanfare horn (H2)
- Right fanfare horn (H2/1)
- Also for code (B03) ECO start/stop function:
- On-board electrical system decoupling relay (K19/7)
- Additional battery relay for ECO start/stop function (K114)
- Windshield washer system pump (M5/1)
- Headlamp cleaning system pump (M5/2)
- Coolant circulation pump (M13/5)
- Also with code (875) Heated windshield washer system:
- Spray nozzle heater (R2/1)
- Spray nozzle hose heater (R2/11)
- Wiper park position heater (R2/10)
- Additionally with code (301) Ashtray package/smoker package:
- Ashtray illumination (R3e1)
- Fresh air/recirculated air flap switchover valve (Y13)

Instrument panel LIN
The following components are actuated over an instrument panel LIN by the processor responsible for controlling the basic functions:
- Analog clock
- Upper control panel control unit
- Automatic transmission transmission mode button
- Chassis button group (with code (488) Steel/air suspension or code (489) AIRmatic (air suspension with continuously adjustable damping))

Wiper/inside rearview mirror LIN
The following components are actuated over a wiper/inside rearview mirror-LIN by the processor responsible for controlling the basic functions:
- Inside rearview mirror (A67)
- Garage door opener
- Wiper motor (M6/1)




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