GF54.00-P-0005GM CAN Data Bus, Function

GF54.00-P-0005GM CAN Data Bus, Function
MODEL 463 up to 31.5.12 with ENGINE 113.993





A1 Instrument cluster
N2/7 Restraint systems control unit
N3/10 ME-SFI [ME] control unit
N10/1 Front signal-acquisition and actuation module (SAM)
N10/2 Rear signal acquisition and actuation module (SAM)
N15/3 ETC control unit
N15/5 Electronic selector lever module control unit
N22 AAC [KLA] control and operating unit
N47-5 ESP and BAS control unit
N73 EIS [EZS] control unit
N80 Steering column module
X11/4 Data link connector
CAN-B CAN data bus, body
CAN-C CAN data bus, engine

CAN stands for " Controller Area Network". This is an electrical bus system for carrying data over two wires.
The tasks are:
^ Data interchange between the individual control units
^ Readying sensor signals for several systems
^ Reducing the number of wires
^ Improving the electromagnetic compatibility (EMC)
The CAN data bus consists of a special twisted two-core data line that connects all CAN users (control units) in parallel.
The two wires of the data line must not be mixed up (low level / high level). The motor electronics (N3/10) control unit is always a consumer with regard to bus adaptation.
A 120 ohms terminating resistor is therefore installed in the motor electronics control unit.
The data are transmitted digitally over the CAN databus 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. Each connected control unit is able to transmit or receive data (bidirectional bus).
The sum of the data blocks, the short break between two transmission intervals and additional properties of the CAN data bus are checked constantly. Detected faults are stored and placed in the fault memory.
In the vehicle a distinction is made between a fast (500 kbit/s) engine CAN data bus (CAN-C) for the drive systems and chassis systems and the slower (83.3 kbit/s) body CAN data bus (CAN-B) structure for the vehicle interior.
The interface of the two CAN data buses (Gateway) is located in the EIS [EZS] control unit (N73).
The instrument cluster (A1) and steering column module (N80) are connected both with the body CAN data bus and with the engine CAN data bus and exchange data with both data bus systems. However, they do not serve as an interface (gateway) between both data bus systems!
When a control unit is replaced, the new control unit must be coded again.
This control unit coding is possible via a STAR DIAGNOSIS menu.
The international standardized network management "OSEK" (open systems and their interfaces for electronics in vehicles) is used for all control units on the CAN data bus.