GF54.21-P-4170LE Central Gateway Control Unit, Component Description
GF54.21-P-4170LE Central Gateway Control Unit, Component Description
- MODEL 216.3, 221.0 /1 as of Model Year 09 /Modification year 08
Illustrated on model 221.0
N93 Central gateway control unit
Location
The central gateway control unit is located on the left in the direction of travel behind the footwell cover on the instrument panel support.
Tasks
The central gateway control unit has the following tasks:
- Reading in of signals
- Gateway
- Actuation of components
- Service processor Data container
- System diagnosis
- Global variant coding
- Monitoring the CAN bus idle
Reading in of signals
The input factors are read in with the following connections:
- Central CAN
- Interior CAN
- Chassis CAN
- Front end CAN
- Diagnostic CAN
Central CAN
The signals are read in by the central gateway control unit via the central CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
Interior CAN
The signals are read in by the central gateway control unit via the interior CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
Chassis CAN
The signals are read in by the central gateway control unit via the chassis CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
Front end CAN
The signals are read in by the central gateway control unit via the front end CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
Diagnostic CAN
The primary purpose of the diagnostic CAN is to allow connection of an external tester. The control units are diagnosed using the tester. This is achieved via diagnosis request messages which the tester sends to the control unit in question. The central gateway control unit responds to the respective message with a diagnosis response message.
For code (359) TELE AID emergency call system in addition the emergency call system control unit (N123/4) is connected to the diagnosis CAN. The emergency call system control unit requires information from the interior CAN and from the chassis CAN.
Gateway
The central gateway control unit is the interface of the above listed CAN buses. It has the task of transmitting information from one CAN bus to other CAN buses.
Actuation of components
Components are actuated with the following lines:
- Central CAN
- Interior CAN
- Chassis CAN
- Front end CAN
Central CAN
The signals are transmitted by the central gateway control unit via the central CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
Interior CAN
The signals are transmitted by the central gateway control unit via the interior CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
Chassis CAN
The signals are transmitted by the central gateway control unit via the chassis CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
Service processor
The maintenance computer is integrated in the central gateway control unit and determines the next due service time from measured values or data from the read-only memory. Here the mileage and time-dependent variables are calculated with each other; and it remains possible to configure different vehicle uses. The maintenance interval display provides the maintenance computer with data on the condition of the engine oil.
Data container
The data container in the central gateway control unit is a nonvolatile mobile data memory.
Use: Within the production flow-through vehicle-specific, test location- specific or control-unit specific data are stored in the data container (e.g. production number, test status, partial tests not run through). These data can be used in the subsequent tests for test sequence control. The total size of the data memory is 128 bytes.
Front end CAN
The signals are transmitted by the central gateway control unit via the front end CAN.
The resultant functions are described in the respective function descriptions (see block diagram or function schematic).
System diagnosis
The system diagnosis is integrated in the central gateway control unit as a software module. Some on-board functions are realized by the central gateway control unit for off-board diagnosis:
- CAN line diagnosis
- CAN SPECIFIED/ACTUAL configuration
- Data logger for telediagnosis
Global variant coding
The central gateway control unit routes global information such as model series and national version over the various CAN buses to the networked control units. These data are processed cyclically by the central gateway control unit on the CAN buses. The control units carry out part of their configuration depending on this information.
Monitoring CAN bus idle
Control units are determined which keep the CAN bus awake in the event of a likely CAN bus standby. This information is filed in a nonvolatile memory. Even after the on-board electrical system battery discharges with a subsequent reset of (G1) the networked control units, it can be determined whether the discharge of the on-board electrical system battery was due to the network or due to an individual CAN subscriber.
