Component Description For Front SAM Control Unit With Fuse And Relay Module - GF54.21-P-6070RD

Model 172.4 

Shown on model 172.4 up to 29.02.2016 

Location 

The front SAM control unit is located on the left-hand side in the engine compartment between the suspension strut tower and the firewall.

Tasks 

Two microprocessors are installed in the front SAM control unit, one for control of basic functions, e.g. the exterior lights, 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 a 3D 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 (interface CAN) 
• Data container 
• System diagnosis 
• Global variant coding 
• Monitoring CAN bus idle 

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

• Interior CAN and LIN interface 
• Reading in of sensors 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 

Central gateway (interface CAN) 

The processor for controlling the central gateway functions acts as the interface between the following CAN bus systems:

• Interior CAN
• Diagnostic CAN (CAN D)
• Chassis CAN (CAN E), up to 29.02.2016
• Chassis CAN 1 (CAN E1), as of 01.03.2016
• Chassis CAN 2 (CAN E2), as of 01.03.2016
• Front end CAN (CAN G), up to 29.02.2016

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, data are logged which refer to the vehicle, the test location or the control units (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 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 bus systems:

• Instrument panel LIN (LIN 1)
• Wiper/inside rear-view mirror LIN (LIN 2)
• Interior CAN

Reading In Of Sensors And Signals 

The input factors are read in over the following connections:

• Direct Line 
• Instrument Panel LIN 
• Wiper/Inside Rearview Mirror LIN 
• CAN 

Direct Line 

The processor for actuating the base functions reads in the signals of the following components over direct lines:

• Refrigerant pressure sensor (B12)
• Outside temperature sensor (B14)
• Exterior lights switch (S1)
• Right front brake wear sensor (S10/2)
• Right rear brake wear sensor (S10/4)
• Brake fluid level switch (S11)
• Backup lamp switch (S16/2) (transmission 711, 716)
• Coolant level switch (S41)
• Windshield washer system fluid level switch (S42)
• ECO start/stop function additional battery (G1/13) (as of 01.03.2016 standard equipment, up to 29.02.2016 with code B03 (ECO start/stop function))
• Right engine hood contact switch (S62/42) (as of 01.03.2016 except code U60 (Active engine hood (pedestrian protection)), up to 29.02.2016 with code B03 (ECO start/stop function) and except code U60 (Active engine hood (pedestrian protection)))

Instrument Panel LIN 

The processor for controlling the basic functions reads in the signals from the following component over the instrument panel LIN:

• Upper control panel control unit (N72/1)

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 rear-view mirror LIN:

• Overhead control panel control unit (N70)
• Garage door opener (A67n2) (with code 231 (Garage door opener) or code 232 (Garage door opener))
• Light sensor (B38/1) (except code 345 (Windshield wiper with rain sensor))
• Rain/light sensor (B38/2) (with code 345 (Windshield wiper with rain sensor))
• Vehicle interior humidity and temperature sensor (B82)
• Forward mirror dimming light sensor (A67h1) (with code 249 (Automatically dimming mirror))
• Backward mirror dimming light sensor (A67h2) (with code 249 (Automatically dimming mirror))

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, up to 29.02.2016
• Chassis CAN 1 (CAN E1), as of 01.03.2016
• Chassis CAN 2 (CAN E2), as of 01.03.2016
• Diagnostic CAN
• Front end CAN, up to 29.02.2016

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:

• Exterior lights
• Interior illumination
• Windshield wiper system
• Central locking
• Windshield washer system heater (with code 875 (Heated windshield washer system))
• Headlamp cleaning system (with code 600 (Headlamp cleaning system))
• Decoupling of on-board electrical system battery and activation of ECO start/stop function additional battery (as of 01.03.2016 standard equipment, up to 29.02.2016 with code B03 (ECO start/stop function))

Actuation Of Components 

The actuation of the components takes place via the following connections:

• Direct Line 
• Instrument Panel LIN 
• Wiper/Inside Rearview Mirror LIN 

Direct Line 

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

• Refrigerant compressor with magnetic clutch (A9/7) (with code B09 (Refrigerant compressor with magnetic clutch))
• Left front lamp unit (E1) (except code 640 (High Performance LED) and except code 641 (Dynamic left-hand traffic LED headlamp) and except code 642 (Dynamic right-hand traffic LED headlamp))
• Headlamp cleaning system pump (M5/2) (with code 600 (Headlamp cleaning system))
• Coolant circulation pump (M13/5)
• Spray nozzle hose heater (R2/11) (with code 875 (Heated windshield washer system))
• Cigarette lighter illumination with ashtray illumination (R3) (with code 301 (Smoker's package))
• Switch illumination for exterior lights switch
• Switch illumination for electric parking brake switch (S76/15)
• Left illuminated door sill molding (E17/35) (with code U25 (Door sills with "Mercedes-Benz" lettering, illuminated))
• Right illuminated door sill molding (E17/36) (with code U25 (Door sills with "Mercedes-Benz" lettering, illuminated))
• Left front center console ambiance illumination (E43/14) (with code 877 (Ambiance illumination))
• Left daytime running lights headlamp (E1/3) (up to 29.02.2016)
• Right front lamp unit (E2) (except code 640 (High Performance LED) and except code 641 (Dynamic left-hand traffic LED headlamp) and except code 642 (Dynamic right-hand traffic LED headlamp))
• Right daytime running lights headlamp (E2/3) (up to 29.02.2016)
• Left front fog lamp (E5/1) (except code 240 (LED daytime running lights) and except code 615 (Bi-xenon headlamp with active curve illumination) and except code 621 (Intelligent Light System (left-hand traffic)) and except code 622 (Intelligent Light System), up to 31.05.2015)
• Right front fog lamp (E5/2) (except code 240 (LED daytime running lights) and except code 615 (Bi-xenon headlamp with active curve illumination) and except code 621 (Intelligent Light System (left-hand traffic)) and except code 622 (Intelligent Light System), up to 31.05.2015)
• Glove compartment lamp (E13/1)
• Right footwell lamp (E17/15) (with code 876 (Interior lights package) or as of 01.03.2016 with code 877 (Ambiance illumination))
• Left footwell lamp (E17/16) (with code 876 (Interior lights package) or as of 01.03.2016 with code 877 (Ambiance illumination))
• Left fanfare horn (h2)
• Right fanfare horn (h2/1)
• ECO start/stop function additional battery (K114) (as of 01.03.2016 standard equipment, up to 29.02.2016 with code B03 (ECO start/stop function))
• Decoupling relay (F32k1) (as of 01.03.2016 standard equipment, up to 29.02.2016 with code B03 (ECO start/stop function))
• Windshield washer system pump (M5/1)
• Left rear center console ambiance illumination (E43/15) (with code 877 (Ambiance illumination))
• Right front center console ambiance illumination (E43/16) (with code 877 (Ambiance illumination))
• Right rear center console ambiance illumination (E43/17) (with code 877 (Ambiance illumination))
• Armrest stowage compartment illumination (E36/1) (with code 876 (Interior lights package))

Instrument Panel LIN 

The following components are actuated over an instrument panel LIN by the processor responsible for controlling the basic functions:

• Analog clock (A70/1) (with code 246 (Analog clock))
• Upper control panel control unit

Wiper/Inside Rearview Mirror LIN 

The following components are actuated over a wiper/inside rear-view mirror-LIN by the processor responsible for controlling the basic functions:

• Inside rearview mirror (A67) (with code 249 (Automatically dimming mirror))
• Garage door opener
• Wiper motor (M6/1)

	Wiring diagram for front SAM control unit with fuse and relay module (N10/1)	Model 172.4 Specification 1	PE54.21-P-2106-97TAA
		Model 172.4 Specification 2	PE54.21-P-2106-97TAB
		Model 172.4 Specification 3	PE54.21-P-2106-97TAC
		Model 172.4 Specification 4	PE54.21-P-2106-97TAD
		Model 172.4 Specification 5	PE54.21-P-2106-97TAE
		Model 172.4 Specification 6	PE54.21-P-2106-97TAF
		Model 172.4 Specification 7	PE54.21-P-2106-97TAG
		Model 172.4 Specification 8	PE54.21-P-2106-97TAH