A method detects and localizes a failure of a measurement acquisition channel in an acquisition system including two redundant acquisition channels for the measurement of a physical quantity in an environment. The method uses a processor with a memory storing a model including modeled values of the physical quantity based on measurements of other physical quantities in the environment. The method includes detecting a symptomatic error of a defective acquisition channel when a deviation between the measured values of the two channels reaches a detection threshold, waiting to let the acquisition system evolve for a certain period, and localizing the defective channel among the two channels, when the deviation of the values measured between the channels reaches a localization threshold different from the detection threshold. The localization is made from the comparison of the measured value of each of the channels with a modeled value of the physical quantity.