1. A method for fault diagnosis in control systems in an internal combustion engine in a motor vehicle, which monitors the operational capacity of sensors, actuators and/or system functions and on identification of a fault symptom determines the actual cause of the fault, comprising the steps of: intervening in the functions of the control systems by a diagnosis manager such that only the smallest possible restriction results for operation of the motor vehicle, collecting all the information by the diagnosis manager relating to at least one fault symptom, which is a possible cause of a fault, and determining the actual cause of one or a plurality of faults with reference to a fault profile of the symptoms.