A device (1) includes a pumping device (7) and a control unit (70) and is configured to test the operational capability of a gas guide element (3) in a gas-measuring system (11) that includes a gas sensor (5). The control unit (70) carries out steps with two operating states including delivering a test gas (91) by the pumping device (7) through the gas guide element (3) to a remote measuring location (80) and is subsequently delivered from the measuring location (80) to the gas sensor (5). Measured values of a gas concentration are detected by the gas sensor (5) during the delivery from the remotely located measuring location (80) to the gas sensor (5) and analyzed to determine whether changes occurring in the detected gas concentration during the delivery from the measuring location (80) to the gas sensor (5) indicate whether the gas guide element (3) is capable of operating.