GF00.19-P-0001RC Overall Network (GVN) Function

GF00.19-P-0001RC Overall Network (GVN) Function
- MODEL 171.4 as of model year 09/YoM 08 model refinement package

General overall network
The increased demands that are made of the vehicle electronics in areas such as the following:
- Vehicle safety
- Comfort
- Communication
- Diagnosis require networking of the existing systems in the vehicle so that the necessary information can be exchanged.

This cannot be achieved using conventional data transfer since the amount of installation space is limited and a reduction of the weight of the vehicle is targeted. This is why data bus systems are used.

The vehicle electronics are networked using the following data bus systems:
- Controller Area Network (data bus/CAN bus) (CAN)
- Media Oriented System Transport (MOST)
- Private bus

CAN
The CAN is an electrical bus system for the transmission of data on two lines.
The CAN consists of a twisted two-core data line that connects all CAN participants (control units) via a parallel connection. The two lines of the data line must not be swapped (low level/high level).
Each connected control unit is able to transmit or receive data (bidirectional bus). The data is transmitted digitally on the CAN at various intervals. The individual data blocks are defined in a data protocol and it is specified which data are received or transmitted by a control unit.

The sum of the data blocks, the short break between two transmission intervals and other properties of the CAN are checked constantly. Detected faults are stored and placed in the fault memory.

The CAN offers the following advantages:
- Data exchange between individual control units
- Readying sensor signals for several systems
- Reducing the number of electrical lines
- Improving electromagnetic compatibility

The following CAN systems are involved in the overall network:
- Interior CAN
- Engine compartment CAN
- Diagnostic CAN
- Vehicle dynamics CAN

Interior CAN
The interior CAN is responsible for data transfers in the vehicle interior. It networks the different comfort systems, for example. The interior CAN operates at a transfer rate of 83.3 kBit/s.

The following control units are subscribers to the interior CAN:
- Instrument cluster (A1)
- Radio (A2) (with code (510) Audio 20 with CD changer or with code (523) MB Audio 20 radio)
- Radio and navigation unit (A2/56) (with code (511) Audio 50 APS with DVD changer or with code (525) MB Audio 50 APS radio)
- COMAND operating, display and controller unit (A40/3) (with code (512) COMAND APS incl. DVD changer or with code (527) COMAND APS with single DVD drive (with navigation))
- Restraint systems control unit (N2/7)
- Driver-side SAM control unit with fuse and relay module (N10/1)
- Rear SAM control unit with fuse and relay module (N10/2)
- HEAT [HAU] control and operating unit (N18) (without code (580) Automatic air conditioning and without code (581) Comfort automatic air conditioning)
- AAC [KLA] control and operating unit (N22) (with code (580) Automatic air conditioning)
- Comfort AAC control and operating unit (N22/7) (with code (581) Comfort automatic air conditioning)
- SH [SIH], AIRSCARF and steering wheel heater control unit (N25/7) (with code (403) AIRSCARF system, with code (443) Steering wheel heater or with code (873) Right and left front seat heaters)
- driver-side front seat adjustment control unit with memory (N32/1) (with code (275) Memory package (driver seat, steering column, mirrors))
- Passenger-side front seat adjustment control unit with memory N32/2 (with code (242) Electrically adjustable front passenger seat with memory)
- Soft top operation control unit (N52)
- PTS control unit (N62) (with code (220) PARKTRONIC)
- Left door control unit (N69/1)
- Right door control unit (N69/2)
- Overhead control panel control unit (N70)
- Upper control panel control unit (N72/1)
- EIS [EZS] control unit (N73)
- Steering column tube module (N80)
- TPM [RDK] control unit (N88) (with code (470) Tire pressure monitor (standard))
- Central gateway control unit (N93)
- Weight Sensing System (WSS) control unit (N110) (with code (494) USA version)

Gateways:
The following control units form interfaces for the exchange of data between the interior CAN and other bus systems:
- Central gateway control unit (interface to engine compartment CAN and diagnostic CAN)
- Radio or COMAND operating, display and controller unit (interface to MOST)

Engine compartment CAN
The engine compartment CAN is responsible for the data transfer between the drive and chassis systems. The engine compartment CAN operates at a transfer rate of 500 kBit/s.

The following control units are subscribers to the engine compartment CAN:
- Instrument cluster
- ME-SFI [ME] control unit (N3/10)
- ETC [EGS] control unit (N15/3) (with transmission 722.6)
- Electronic selector lever module control unit (N15/5) (with transmission 722)
- ESP and BAS control unit (N47-5)
- Headlamp range adjustment control unit (N71) (with code (614) Bi-xenon headlamp unit or code (618) Bi-xenon headlamp)
- EIS [EZS] control unit
- Steering column module
- Central gateway control unit
- Fully integrated transmission control unit (VGS) (Y3/8n4) (with transmission 722.9)

Gateway:
The following control unit forms the interface for the exchange of data between the engine compartment CAN and the other bus systems:
- Central gateway control unit (interface to interior CAN and diagnostic CAN)

Diagnostic CAN
An external tester (e.g. STAR DIAGNOSIS) can be connected via the diagnostic CAN. The diagnostics CAN operates at a transfer rate of 500 kBit/s. In vehicles with code (359) TELE AID emergency call system, the emergency call system control unit (N123/4) is also connected.

The following control units are connected to the diagnostic CAN:
- Emergency call system control unit
- Central gateway control unit
- External tester (e.g. STAR DIAGNOSIS)

Gateway:
The following control unit forms the interface for the data exchange between the diagnostic CAN and the other bus systems:
- Central gateway control unit (interface to interior CAN and engine compartment CAN)

Vehicle dynamics CAN
The vehicle dynamics CAN connects the yaw rate, lateral and longitudinal acceleration sensor (B24/15) to the ESP and BAS control unit. The vehicle dynamics CAN operates at a transfer rate of 500 kBit/s.

MOST
MOST is an optical networking system. Here, data are transferred via fiber optic cable to the connected information, navigation, and communication components. The MOST operates with a transfer rate of 22 Mbits/s.

The following control units are connected to MOST:
- Radio or
- Radio and navigation unit or
- COMAND operating, display and controller unit
- Amplifier for sound system (N40/3) (with code (810) Sound system)
- Digital Audio Broadcasting control unit (N87/3) (with code (537) Digital radio or code (833) Great Britain version)
- SDAR control unit (N87/5) (with code (536) SIRIUS satellite radio)
- Media interface control unit (N125/1) (with code (518) Media interface)

Gateway:
The following control unit forms the interface for the exchange of data between the MOST and the interior CAN:
- Radio or COMAND operating, display and controller unit

Private bus
The EIS [EZS] control unit and the electric steering lock control unit (N26/5) are linked for exchanging data via the private bus.