The control modules are connected to a complex communication network called CAN-Bus (Controller Area Network). It is through this network that the working parameters and various information are exchanged between the modules. Each controller has stored messages, which are necessary to send at the time of starting the data transmission, and through which you can determine the availability of the transmitter module.
The communication networks are HS-CAN (High-Speed Controller Area Network), MS-CAN (Medium Speed Controller Area Network), and the I-CAN (Infotainment Controller Area Network). Diagnostic code U0009 OBDII will be set when the High-Speed CAN Bus has a malfunction caused by a short circuit.