GF00.19-P-0001RTJ Overall Network (GVN) Function
GF00.19-P-0001RTJ Overall Network (GVN) Function
- MODEL 251
- with CODE (498) Japan version up to Model Year 8
Illustrations of CAN C bus
A1 Instrument cluster
A76 Left front reversible emergency tensioning retractor
A76/1 Right front reversible emergency tensioning retractor
A80 Intelligent servo module for DIRECT SELECT
G2 Generator
N2/7 Restraint systems control unit
N3/10 ME control unit
N47-5 ESP control unit
N51 AIRmatic with ADS control unit
N71 Headlamp range adjustment control unit
N73 EIS [EZS] control unit
N80 Steering column module
N93 Central gateway control unit
N97 Rear axle level control system control unit
X11/4 Data link connector
Y3/8 Electric control unit (VGS)
CAN B Controller Area Network bus Class B (interior compartment) (CAN-B)
CAN-C Controller Area Network bus Class C (engine compartment) (CAN-C)
CAN-D Controller Area Network bus class D (diagnosis)
LIN Local interconnect network (LIN)
MFL Multifunction steering wheel
Illustration of CAN B bus
1 Center nozzles air flap control
2 Rear fond blower motor air flap control
3 MOST bus
A1 Instrument cluster
N10 Front SAM ECU
N10/8 Rear SAM control unit
N22 AAC [KLA] control and operating unit
N22/7 Comfort AAC [KLA] control and operating unit
N25/7 HS [SIH], seat ventilation and steering wheel heater control unit
N32/1 Driver front seat adjustment control unit with memory
N32/2 Front passenger front seat adjustment control unit with memory
N62 PTS control unit
N69/1 Door control unit front left
N69/2 Door control unit front right
N70 Overhead control panel control unit
N72 Lower control panel control unit
N72/1 Upper control panel control unit
N72/2 RCP [HBF] control unit
N73 EIS [EZS] control unit
N93 Central gateway control unit
N93/1 Audio gateway control unit
N121/1 Rear-end door closing control unit
S1 Exterior lamp switch
CAN B Controller Area Network bus Class B (interior compartment) (CAN-B)
CAN-C Controller Area Network bus Class C (engine compartment) (CAN-C)
LIN Local interconnect network (LIN)
MOST Media Oriented System Transport (MOST)
Illustration of MOST bus
A2/6 CD changer
A40/3 COMAND operating, display and control unit
N40/3 Amplifier for sound system
N41/5 Microphone array control unit
N93/1 Audio gateway control unit
CAN B Controller Area Network bus Class B (interior compartment) (CAN-B)
MOST Media Oriented System Transport (MOST)
W Wake-up line
Overall network
The further advancement of driver information systems is reflected in the demands placed on data bus systems. A data bus is a data collection line, the data of which can be used by all the control units connected.
Function
Most control units of the vehicle are linked to each other via data bus lines, in other words there is no direct electrical connection between a sensor and the executing actuator.
A corresponding message (data) is generated using the sensor signal and made available to the data bus system. However, the data flow must be controlled using an access procedure (log) if all control units utilize a common bus line.
Data bus systems
5 data bus systems are involved in the networking:
- Controller Area Network bus Class B (interior compartment) (CAN-B)
- Controller Area Network bus Class C (engine compartment) (CAN-C)
- Controller Area Network bus class D (diagnosis)
- Media Oriented System Transport (MOST)
- Local Interconnect Network bus
The operational field is differentiated as follows:
- CAN-B links the control units of systems located in the vehicle interior (e.g. power windows, heated rear window etc.).
- CAN-C links the control units for the drive and chassis systems (e.g. engine, transmission control etc.).
- CAN-D links the central gateway control unit with the data link connector to perform diagnosis on all networked control units. Moreover, the emergency call system control unit can be addressed over this CAN bus.
- MOST links the control units of the audio systems and navigation systems (e.g. telephone, voice control etc.) via a fiber optic cable.
- The LIN bus is used where rather simple control and monitoring tasks are to be performed in the vehicle.
Higher demands are placed on the CAN-C with regard to immunity to interference, e.g. with respect to electromagnetic effect or radiation and the data transfer rate.
CAN bus systems
CAN bus systems refer to double-wire bus systems. They differ from one another in terms of transfer rate. The CAN B bus is the slowest.
MOST bus
The MOST bus is an optical bus system. Here the data are transferred via fiber optical cables to the connected control units for information, navigation, and communication systems. It has the fastest transfer rate.
LIN bus
The LIN bus is a single-wire bus system. Compared to the other bus systems, the LIN bus is slow. It is used between the multifunction steering wheel and the steering column module as well as in the air conditioning system. Likewise, it can be found between the upper control panel control unit and the lower control panel control unit as well as between the upper control panel and the rotary light switch.
Data exchange between data bus systems
The radio or the COMAND operating, display and control unit forms the interface (gateway) for data exchange between the MOST and CAN-B. The central gateway control unit is the interface for data interchange between the CAN-B and the CAN-C.
The central gateway control unit is also the CAN-D interface to the data link connector. The control units connected to a wide variety of system buses can be tested using STAR DIAGNOSIS.
The steering column module, the instrument cluster and the EIS [EZS] control unit are connected both to the CAN-B and the CAN-C. However, they do not act as an interface (gateway) between the two data bus systems. The steering column module reads in the switch actuations on the steering column module and all button actuations on the multifunction steering wheel (MFL) over the LIN bus and places them on the CAN-B. The angle of the steering wheel is measured by the steering angle sensor (N49) and transferred to the CAN C bus via the steering column module.
