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

MODEL 218 

Location 

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

Task 

Two microprocessors are installed in the front SAM control unit, one for control of the 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 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 (interface CAN) 
• 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 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 

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

Central gateway (interface CAN) 

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

• Interior CAN
• Diagnostic CAN (CAN D)
• Chassis CAN (CAN E) (up to 28.02.2013) or chassis CAN 1 (CAN E1) (as of 01.03.2013)
• Front end CAN (CAN G) (up to 28.02.2013) or chassis CAN 2 (CAN E2) (as of 01.03.2013)

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 via 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 onboard 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 via 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)
• Left rear level sensor (B22/7) (without CODE 488 (Steel/air suspension) and without CODE 489 (AIRMATIC (air suspension with continuous adjustment damping)))
• Interior temperature sensor with integrated fan (N70b1) (with CODE 414 (Electric glass tilting/sliding roof))
• Interior temperature sensor with integrated fan (N70/3b1) (without CODE 414 (Electric glass tilting/sliding roof))
• Interior lamp automatic function switch (N70/3s3) (without CODE 414 (Electric 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)
• Automatic transmission mode button (S16/12)
• Chassis button group (S77) (with CODE 488 (Steel/air suspension) or CODE 489 (AIRMATIC (air suspension with continuous adjustment 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 rear-view mirror LIN:

• Forward-facing mirror dimming light sensor (A67h1) (with CODE 249 (Automatically dimming interior rearview mirror and outside mirrors including folding outside mirrors))
• Rear-facing mirror dimming light sensor (A67h2) (with CODE 249 (Automatically dimming interior rearview mirror and outside mirrors including folding outside mirrors))
• 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:

• Diagnostic CAN
• Chassis CAN (up to 28.02.2013) or chassis CAN 1 (as of 01.03.2013)
• Front end CAN (up to 28.02.2013) or chassis CAN 2 (as of 01.03.2013)

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)
• Windshield wiper system
• Windshield washer heater (with CODE 875 (Heated windscreen washing system))
• Central locking (ZV)
• Headlamp cleaning system
• Decoupling of on-board electrical system battery and activation of ECO start/stop function additional battery (G1/13) (up to 31.08.2014 with CODE B03 (ECO start/stop function) and engine 276)

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 (A9) (without CODE B09 (Refrigerant compressor with magnetic clutch))
• Refrigerant compressor with magnetic clutch (A9/7) (with CODE B09 (Refrigerant compressor with magnetic clutch))
• Left front lamp unit (E1)
• Left daytime running lights headlamp (E1/3) (up to 31.08.2014)
• Right front lamp unit (E2)
• Right daytime running lights headlamp (E2/3) (up to 31.08.2014)
• Glove compartment lamp (E13/1) over glove compartment lamp switch (S17/9)
• Right front footwell lamp (E17/15)
• Left front footwell lamp (E17/16)
• Left rear footwell lamp (E17/17)
• Right rear footwell lamp (E17/18)
• Left fanfare horn (H2)
• Right fanfare horn (H2/1)
• Windshield washer system pump (M5/1)
• Headlamp cleaning system pump (M5/2)
• Coolant circulation pump (M13/5)
• Fresh air/recirculated air flap switchover valve (Y13)
• Left front side marker lamp (E6/1) (with CODE 460 (Canada version) or CODE 494 (USA version))
• Right front side marker lamp (E6/2) (with CODE 460 (Canada version) or CODE 494 (USA version))
• Center console ambiance illumination (E43/6) (with CODE 877 (Ambiance illumination))
• Driver instrument panel ambiance illumination (E43/7) (with CODE 877 (Ambiance illumination))
• Front passenger instrument panel ambiance illumination (E43/8) (with CODE 877 (Ambiance illumination))
• On-board electrical system decoupling relay (K19/7) (up to 31.08.2014 with CODE B03 (ECO start/stop function) and engine 276)
• ECO start/stop function additional battery relay (K114) (up to 31.08.2014 with CODE B03 (ECO start/stop function) and engine 276)
• Spray nozzle heater (R2/1) (with CODE 875 (Heated windshield washer system))
• Wiper park position heater (R2/10) (with CODE 875 (Heated windshield washer system))
• Spray nozzle hose heater (R2/11) (with CODE 875 (Heated windshield washer system))
• Ashtray illumination (R3e1) (with CODE 301 (Ashtray package/smoker 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
• Upper control panel control unit
• Automatic transmission mode button
• Chassis button group (with CODE 488 (Steel/air suspension) or CODE 489 (AIRMATIC (air suspension with continuous adjustment damping)))

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 rear-view mirror (A67)
• Garage door opener (with CODE 231 (Garage door opener) or CODE 232 (Garage door opener with frequency 284-390 MHz))
• Wiper motor (M6/1)

Wiring diagram for front SAM control unit with fuse and relay module (N10/1)

Model 218 Sheet 1 Model 218 Sheet 2 Model 218 Sheet 3 Model 218 Sheet 4 Model 218 Sheet 5 Model 218 Sheet 6 Model 218 Sheet 7 Model 218 Sheet 8 Model 218 Sheet 9

PE54.21-P-2106-97XAA PE54.21-P-2106-97XAB PE54.21-P-2106-97XAC PE54.21-P-2106-97XAD PE54.21-P-2106-97XAE PE54.21-P-2106-97XAF PE54.21-P-2106-97XAG PE54.21-P-2106-97XAH PE54.21-P-2106-97XAI