Remote diagnosis of data processing units

Disclosed is a diagnostic unit for a remote diagnosis of a data processing unit (DPU). The diagnostic unit is adapted to be coupled to a remote DPU via a network and to an internal bus of the DPU. The diagnostic unit includes a central processing unit (CPU) for controlling a diagnostic action and/or a monitoring action independently of the DPU, by monitoring a data communication within the DPU and/or of the DPU with external devices, and/or by performing tests with the DPU. An "intelligent" diagnosis of the DPU can thus be provided, allowing a continuous and on-going monitoring of the DPU independent of the functional state of the DPU.