This paper presents a study of the potential of integrated services for app-based system diagnosis using mobile information systems. First, a task and context analysis is provided for the application of integrated system diagnosis in the context of plant asset management (PAM). Second, exemplary scenarios are presented which demonstrate IT services for system analysis based on self-organizing maps, system diagnosis with a graph-based approach and support for therapeutic measures on defective assets. Third, a mobile information system is presented that allows users to list, describe, filter, and select assets, to browse through available diagnoses, and to follow step-by-step instructions for recommended therapeutic measures. The mobile information system provides a graphical representation, description, and selection of assets by using a P&I diagram as well as a chart visualization of process values. The system further provides access to both static and transient data sources such as engineering data of the plant, process data of the technical process and the results of complex analysis services. This mobile information system demonstrates the suitability of the proposed app-based approach. Finally, the results of a focus group workshop are summarized, showing the potential of mobile information systems in an industrial setting, barriers that still remain.