A vehicle multiplexing bus system must be provided with monitoring capability so that transmission, transaction, and reception errors can be detected. This would include the check signal in the data frame and monitoring components in a transmission. It is a feature of a multiplex bus that each transmitter receives its own transmitted message again and by file comparison can detect any deviation or corruption. If a station identifies an error, it sends out an error flag that halts the current trans-mission. This prevents other stations from receiving a faulty message.
In the event of a major station defect, it is possible that all messages, both good and bad, might be terminated with an error flag. To protect against this, a multiplex bus system has a built-in function that enables it to distinguish between intermittent and permanent errors. Furthermore, this feature can sometimes localize station failures and route the data network to an appropriate failure strategy. The process of localizing a station-type failure is based on statistical evaluation of error factors, so it is not entirely foolproof.