Dynamic Electrochemical Impedance Spectroscopy (DEIS) was presented as novel method for diagnostic and monitoring of PEMFC stack and single cells operation. Impedance characteristics were obtained simultaneously with current - voltage characteristics for stack and each individual cell. Impedance measurements were performed in galvanodynamic mode. It allowed to compare performance of each cell and identification of faulty cell operation for activation, ohmic and mass transfer losses regions. The biggest difference in impedance value between healthy and faulty cell was registered for mass transfer losses region. The authors discussed the statistical selection of an equivalent circuit based on the course of chi(2) value in the function of current. (C) 2018 Elsevier Ltd. All rights reserved.