Monitoring Function: Communication
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2010 BMW M6, 2010 BMW M5, 2009 BMW M6, 2009 BMW M5, and 2008 BMW M6. However, it is still accessible from the selected car via links, so may be relevant.
The Communication is checked continuously. If no message is received after a certain time, a timeout (U114B, U114E, U115B) is detected. If a message is received, the Alivecounter must be different to the last message, else the fault codes U114A, U114D or U115A are set. Next a checksum is calculated and is compared to the received checksum: they must be equal, else the errors U114C, U114F or U115C are detected.
If there is an electronic-problem (short between can-high and can-low) the CAN-controller detects a Bus-Off by himself (UC140).