A method of testing a system having at least one electrochemical sensor for detecting an analyte gas within a housing of the system, the housing having an inlet, the at least one electrochemical sensor including an electrically active working electrode in fluid connection with the inlet of the system, the method including biasing the electrically active working electrode at a first potential, to detect the analyte gas and biasing the electrically active working electrode at a second potential, different from the first potential, such that the at least one electrochemical sensor is sensitive to a driving force created in the vicinity of the inlet to test at least one transport path of the system. The method may further include creating the driving force in the vicinity of the inlet of the housing of the system and measuring a response of the electrically active working electrode to the driving force.