DIAGNOSTIC DEVICE FOR A MULTI-VOLTAGE VEHICLE ELECTRICAL SYSTEM, A MULTI-VOLTAGE VEHICLE ELECTRICAL SYSTEM, AND A METHOD FOR OPERATING A MULTI-VOLTAGE VEHICLE ELECTRICAL SYSTEM

摘要

A diagnostic device is provided for a multi-voltage electrical system of a motor vehicle which has a first subnetwork acted on by a first voltage and a second subnetwork acted on by a second voltage, the first voltage being higher than the second voltage, and the first and the second subnetwork having a shared ground connection. The diagnostic device includes a second ground connection, a measuring unit configured to measure a current flow via the second ground connection, and a diagnostic unit configured to diagnose a disturbance in the shared ground connection and/or in the second ground connection on the basis of the measured current flow via the second ground connection as a function of at least one operating state of the vehicle electrical system.