Considering the complexity of the electrical behavior (polarization curve and impedance spectrum) of PEFC and the lack of relevant models that could be used to identify the main transport parameters in Membrane Electrode Assemblies (MEA), a semi-analytical pseudo-bidimensionnal model is currently developed. Its main characteristics are first recalled. Then the results of a full numerical two-dimensional model are compared to those of the pseudo-bidimensionnal approach and analyzed. It is shown that oxygen diffusion inside the GDL can be considered as a 1D diffusion without any appreciable discrepancy and that the electrode can be modeled as a plane without major error either on impedance spectrum or polarization curve. Oxygen diffusion through the gas channel reveals an important discrepancy between volumetric and plane descriptions, leading to the necessity of a more complex model of the fluid flow in the gas channel.