Abstract: An internal combustion engine has a crankcase and a crankcase ventilation system having a switchable shut-off valve, and sensors that detect different operating parameters of the engine, including a load variable of the engine. An estimated load parameter is determined based on the different detected operating parameters using a dynamic model, and a corrective value of a characteristic value is determined as a function of a deviation between the estimated load variable and the detected load variable. To implement a diagnosis, diagnosis switching cycle(s) are controlled, in which the shut-off valve is set to a closed switched position for a first time and set to an open switched position for a second time. A diagnosis value representative of a shut-off valve being in a correct or incorrect state is determined based on a change to the corrective value in response to the one or the plurality of diagnosis switching cycles.

Abstract: To operate an internal combustion engine, a specified forced stimulation is applied to an air ratio as the basis for a target value of a lambda controller. In diagnostic operation, a diagnostic function is used to identify a probe error of the exhaust gas probe, and a value of the measurement signal is recorded as a start value in chronological correlation with an edge of the target value curve of the lambda controller and the current value of the measurement signal is recorded as an end value after a specified first time duration. The start and end values are used to determine whether a filter error or a dead time error of the exhaust gas probe exists. The first time duration is specified such that start value/end value difference for a filter error differs start value/end value difference for a dead time error by at least a specified difference value.

Abstract: An internal combustion engine has a crankcase and a crankcase ventilation system having a switchable shut-off valve, and sensors that detect different operating parameters of the engine, including a load variable of the engine. An estimated load parameter is determined based on the different detected operating parameters using a dynamic model, and a corrective value of a characteristic value is determined as a function of a deviation between the estimated load variable and the detected load variable. To implement a diagnosis, diagnosis switching cycle(s) are controlled, in which the shut-off valve is set to a closed switched position for a first time and set to an open switched position for a second time. A diagnosis value representative of a shut-off valve being in a correct or incorrect state is determined based on a change to the corrective value in response to the one or the plurality of diagnosis switching cycles.

Abstract: To operate an internal combustion engine, a specified forced stimulation is applied to an air ratio as the basis for a target value of a lambda controller. In diagnostic operation, a diagnostic function is used to identify a probe error of the exhaust gas probe, and a value of the measurement signal is recorded as a start value in chronological correlation with an edge of the target value curve of the lambda controller and the current value of the measurement signal is recorded as an end value after a specified first time duration. The start and end values are used to determine whether a filter error or a dead time error of the exhaust gas probe exists. The first time duration is specified such that start value/end value difference for a filter error differs start value/end value difference for a dead time error by at least a specified difference value.