Central gateway control module, task - GF00.19-P-4100-01S

Tasks: 

• Gateway between the CAN-B and CAN-C and vice versa a data logger
• Global variant coding (with networked control modules the central gateway control module (N93) passes on global information such as model series and national version to the CAN B and CAN C via the network)
• Router between CAN B and diagnosis CAN
• Router between CAN C and diagnosis CAN
• System diagnosis only for the Telematik support section between CAN B, CAN C and diagnosis CAN
• Data container

3 CAN buses are fitted to the vehicles:

• diagnosis CAN 500 kbit/s
• CAN B (interior) 83.3 kbit/s
• CAN C (engine compartment) 500 kbit/s

Primarily diagnosis CAN serves to connect an external "tester" test instrument in the vehicle. The control modules are diagnosed with the tester. This happens with the help of diagnosis inquiry messages (diagnosis request) which the tester transmits to the relevant control module. The control module answers this message with a diagnosis answer message (diagnosis response).

In addition the communications platform (CP) is connected to the diagnosis CAN. The communications platform (CP) needs information from the CAN interior and CAN engine compartment.

Various control modules are connected to interior CAN. The control modules need information from the engine compartment CAN and diagnosis CAN (CP). Amongst others, drive train control modules are connected to the engine compartment CAN. The control modules need information from the interior CAN and diagnosis CAN (CP).

With the gateway function a distinction is made between various types:

• In normal vehicle operation information which is present on a CAN bus and is needed on another bus for the control module functions is routed by the central gateway control module (N93). This gateway functionality is described as a functional gateway.
• In diagnosis mode, i.e. when an external test instrument is connected, the diagnosis request messages must be routed from the test instrument to the corresponding control modules. Vice versa the diagnosis response messages must be routed from the control module to the test instrument. This gateway functionality is described as diagnosis gateway.
• As the functional CAN buses (engine compartment CAN and interior CAN) are not accessible via the diagnostic socket, the measurements must take place via the diagnosis CAN. The central gateway control module (N93) must therefore route all the CAN messages from the bus to the studied on the diagnosis CAN. This gateway functionality is therefore called application gateway. Application gateway is currently only planned for the engine compartment CAN.