Control or regulation of a settable setting clement with integral behaviour is carried out by firstly detecting the actual value of a parameter of an operating system which incorporates the setting element. A target value of the parameter is also generated, and the setting of the setting element is dependent on the difference between the target and actual values. The actual value of the parameter is also monitored so that an error or defect in the system can be recognised. In response to such an error, the setting element is controlled so that it is disposed at least temporarily in a predetermined setting, thus permitting emergency operation of the system. The element may then be controlled in dependence on a simulated actual value based on the predetermined setting. In the embodiment, the setting element is an injection-adjusting device of a high-pressure fuel pump, and it is driven to a predetermined position under certain engine operating conditions such as over-run or idling.