A method for operating an internal combustion engine and a device for implementing the method, in which a diagnosis is performed of an adjusting device situated in the exhaust duct of the internal combustion engine, which distributes the exhaust gas between a first and at least one second exhaust gas path. A transit time from a change of a characteristic quantity of the exhaust gas in front of the adjusting device until the appearance behind the adjusting device detected by a sensor is compared to a specified transit time threshold value. The transit time threshold value is specified as a function of a setpoint position of the adjusting device. In the event of a deviation from or exceedance of the threshold value, a fault signal is provided.