Recently we have introduced a novel Kelvin probe based approach for spatially highly resolved and highly sensitive measurement of hydrogen in materials and its permeation through materials. In this work we will show how this can be applied for detecting active corrosion sites on the surface of a material from the backside. At the low potentials of actively corroding metal hydrogen uptake occurs at defect sites of the coating and this can be monitored by detecting the resulting higher detectable hydrogen permeation currents at the backside. High lateral resolution is possible in general, however, the achievable resolution is limited by the thickness of the material to be investigated and for longer monitoring times also lateral cross diffusion in the palladium detection layer has to be taken into account. (C) 2013 Elsevier Ltd. All rights reserved.