This document specifies machine-readable descriptions of all fault symptom algorithms which are implemented as diagnostic software in an electronic control unit (ECU). The main use case is the standardized data exchange from a function & software supplier to a vehicle manufacturer (VM) in order to enable a tool-based information processing. Based on the FXD content and associated calibration values, several end user documents can be generated such as the "summary sheet" needed as part of the vehicle type approval documentation package or the “repair and maintenance information” (RMI). The expected main benefits of the FXD approach are an overall efficiency improvement as well as an independency of supplier- and VM-specific format handling.