A device, a method, a computer program and a computer program product for diagnosing an internal combustion engine (100), in which a first cylinder (102) includes a combustion chamber (101), a fuel quantity and a fresh air quantity being supplied to the combustion chamber (101) for combustion; a torque contribution (D), generated by the combustion, of the first cylinder (102) in a first operating mode (B1) of the internal combustion engine (100) being a function of the fresh air quantity supplied, and in a second operating mode (B2) of the internal combustion engine (100) being essentially a function of the fuel quantity, wherein a first variable (L1) characterizing a smooth running of the internal combustion engine (100) in the first operating mode (B1) is ascertained, a second variable (L2) characterizing the smooth running of the internal combustion engine (100) in the second operating mode is ascertained, the first variable (L1) is compared to the second variable (L2), a diagnosis of the internal combustion engine (100) is made as a function of the result of the comparison.