Functional description see BMW Technology:
TIS -> Document -> SI Technology -> 61 02 03 (015)
Brief description:
The data exchange of the control units is across various bus systems with different features. These bus systems are interconnected via so-called gateways. The task of these gateways is to interchange data between the connected bus systems. The bus structure is shown in the adjacent system circuit diagram.
The individual buses are to assigned to the following functional areas in the vehicle:
If faults occur in this communication framework, fault code memory entries are created in the control units involved. Here, a distinction can normally be made between wire faults and logical faults such as missing messages. It should be borne in mind that a fault cause generally causes a number of fault code memory entries in different control units.
The following fault causes can lead to bus faults:
This test module evaluates the fault code memory entries as a whole. The evaluation of the combination of existing fault code memory entries provides the most probably fault cause. The analysis is currently restricted to the CAN and byteflight systems (E65, E60).
If there has been an undervoltage situation in the vehicle, bus faults can also (erroneously) be entered. For this reason, before evaluation of the bus faults, there is a check as to whether an undervoltage fault is stored in more than two control units. If this is the case, there is no further evaluation of the bus faults; the fault cause can be found in the area of the power supply.