DOCUMENTATION OF FAULTS IN A FAULT MEMORY OF A MOTOR VEHICLE

摘要

Method for operating a communication network of a motor vehicle, wherein the communication network comprises a plurality of control devices which are connected to a data bus and interchange messages with one another via said bus. The control devices are connected to a voltage source and have a voltage measuring device for determining the applied voltage. The control devices may also have at least write access to a central or internal fault memory in order to document an item of information relating to a detected fault therein. The method comprises the following steps: a) the supply voltage of the voltage source is determined; b) a check is carried out in order to determine whether the determined supply voltage exceeds an upper voltage threshold or undershoots a lower voltage threshold; c) the control devices are provided with an item of information representing the determined supply voltage and/or with an item of information representing the exceeding or undershooting; d) upon the detection of a fault, a check is carried out using the provided information in order to determine whether the supply voltage exceeds or undershoots the relevant voltage threshold; e) if the supply voltage exceeds or undershoots the threshold, the control device (1) writes, instead of an item of fault information, an item of information representing the fact that the supply voltage exceeds or undershoots the threshold as a possible cause of the fault to the fault memory thereof.