Circuit/System Description

WARNING: This page is about a different car, the 2020 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

An infotainment CAN bus is used to monitor for serial data communications between the A11 Radio and the S165 Infotainment Control Switch during normal vehicle operation. The serial data is transmitted on two twisted wires that allow speeds up to 2 Mbit/s. The twisted pair is terminated with two 120 Ω resistors, one is internal to the A11 Radio and the other is internal to the S165 Infotainment Control Switch. The resistors are used as the load for the infotainment CAN bus during normal vehicle operation. The infotainment CAN bus is a differential bus. The infotainment CAN serial data [ + ] and infotainment CAN serial data [ - ] circuits are driven to opposite extremes from a rest or idle level of approximately 2.5 V. Driving the lines to their extremes, adds 1 V to the infotainment CAN serial data [ + ] circuit and subtracts 1 V from the infotainment CAN serial data [ - ] circuit. If serial data is lost, devices will set a no communication code against the non-communicating device. Note that a loss of serial data DTC does not represent a failure of the device that set it.