Topic:
Gateway:
In the car, several different types of networks may be present, such as CAN-A and CAN-B with different speeds, LIN-bus, and MOST-bus. These networks cannot simply be connected to each other. The light signals of the MOST-bus cannot be detected by the CAN-bus, and the two CAN-bus networks cannot communicate with each other due to the speed difference.
However, it is possible for the car to be diagnosed, with diagnostic equipment connecting to the control units in all networks in the car. The gateway makes this possible. The gateway is also called the “hub” of all networks in the car. An example of this can be seen in the image below.
All networks are connected to the gateway. It essentially translates the information between the different networks. This way, all the control units can still communicate with each other, and the diagnostic computer can connect to all networks. The OBD connector is therefore also connected here. The diagnostic computer can access all networks in the car via the gateway.
If the gateway does not function properly, the different networks in a vehicle can no longer communicate with each other, causing multiple functions to stop working. ECUs that are normally “woken” via the network remain turned off. A non-functioning or poorly functioning gateway may have the following causes:
- power supply and ground are not in order;
- the clamping force of the connector on the pins in the gateway is insufficient;
- the gateway is incorrectly coded, or due to a software/hardware error, the coding has been erased;
- the hardware in the gateway is damaged as a result of a moisture issue, overload, or production problem.
The gateway needs to be coded after it is replaced, or when control units are added. This often occurs after installing a tow hitch with an original tow hitch control unit. After coding, the relevant control unit is accepted into the network, and with the diagnostic equipment, the fault memory can be read, live data viewed, actuators controlled, programmed, etc.
The bottom two images show a gateway (left) of an Audi and on the right the installation location (behind the glove compartment) of this gateway.
