Disclosed is a method for diagnosis of an oxygen probe for a combustion engine, with the steps: When an engine's fuel injection is inactive, measuring the output electric voltage from the oxygen probe; If the measured output electrical voltage of the oxygen probe is greater than a predetermined minimum voltage threshold, measuring a pressure prevailing in an intake distributor of the engine; If the measured pressure in the intake distributor is less than a predetermined minimum pressure threshold, increasing the pressure to a value greater than the predetermined minimum pressure threshold; Determining the time period between the time when the output electrical voltage of the probe falls below a second predetermined voltage threshold and the time when the output electrical voltage of the probe falls below a third predetermined voltage threshold; and diagnosing the oxygen probe depending on elapsed the time period.