GF54.21-P-4170RI Central Gateway Control Unit, Component Description

GF54.21-P-4170RI Central Gateway Control Unit, Component Description
- MODEL 230.4 as of model year 09 /YoM 08 model refinement package






N93 Central gateway control unit

Location
The central gateway control unit is located in the cockpit on the right of the A-pillar in the direction of travel.

Tasks
The central gateway control unit has the following tasks:
- Reading in of signals
- Gateway between interior CAN and engine compartment CAN
- Data container
- Global variant coding

Reading in of signals
The input factors are read in with the following connections:
- Interior CAN
- Engine compartment CAN
- Diagnostic CAN

Interior CAN
The central gateway control unit reads in function-relevant information via the interior CAN.

Engine compartment CAN
The central gateway control unit reads in function-relevant information via the engine compartment CAN.

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.
On vehicles with code (359) TELE AID emergency call system, the emergency call system control unit (N123/4) is also connected to the diagnostic CAN. The emergency call system control unit requires information from the interior CAN and engine compartment CAN.
Gateway between interior CAN and engine compartment CAN In diagnosis mode, i.e. if an external tester is connected, the diagnosis request messages have to be routed from the tester to corresponding control units. Conversely, the diagnosis response messages have to be routed from the central gateway control unit the tester. This gateway functionality is called the diagnosis gateway. Since the interior CAN and engine compartment CAN are not accessible via the diagnostic socket when operating, measurements have to be performed via diagnostic CAN. The central gateway control unit must therefore route all of the CAN messages from the CAN being tested to the diagnostic CAN. This gateway functionality is called the application gateway.

Data container
The data container in the central gateway control unit is a non-volatile mobile data memory.
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.

Global variant coding
For networked control units, the central gateway control unit transmits globally relevant information such as model series and national version over interior CAN and engine compartment CAN.