Coupled multielectrode array sensors (CMAS) have been used for quantitatively monitoring corrosion particularly localized corrosion in laboratories and industrial fields. The internal anodic current on the most anodic electrode in a CMAS may affect the measurement of corrosion by a CMAS in cases where uniform corrosion as opposed to non-uniform corrosion or localized corrosion is dominant. This paper presents a method that automatically determines the effect of the internal current on the corrosion rate measured by the CMAS probe.