An approach to self-diagnosis of the components (modules and communication lines) of nonuniform digital systems consisting of equal numbers of modules of two types (processor, memory) was presented. To carry out checking and self-diagnosis, different connected modules are regarded as subsystems which are checked by the active modules such as processors. Bit-stuck multiple failures of a, limited number of component are permitted, whereas no new failures occur in the course of self-diagnosis. The Barsi-Grandoni-Maestrini model is used to describe the results of subsystem testing. It was assumed that the nonuniform system includes a diagnostic monitor initiating checking kind self-diagnosis. An example of checking and self-diagnosis of the components of a nonuniform 14-module system was presented.