Is designed the approach to the task of complex dynamic object diagnostics on the basis of internal structures features structural analysis. Operational units and links fault symptoms are detected by means of the system transfer quality change control. The task of fault source localization is solved by mean of diagnostic model of topological rank, invariant to the operators classes of blocks and values of their parameters. Is given an example of solving the problem of fault detection and localization of nickel powder technological production process system error source.