Throughout the car, signal wires are connected that connect all the control units (engines, transmissions, power windows, security systems, etc.) to a single network. Through this network, the blocks exchange information with each other and communicate. This is the CAN bus.

All information in the CAN bus is transmitted by broadcast messages - that is, it can be read by any unit connected to the bus and only the receiving unit decides whether it needs this information or not.

To implement the project, it is necessary to catch messages from the CAN bus of the car, going to the "ECU", read the necessary data from them, modify the message and transfer it to the "ECU" in a modified form. It turns out the so-called “Filter” and “Bridge” between the CAN bus of the car and the “ECU” about which the control units have no idea, since for them the whole process is completely transparent.