Method for operating a drive device for a motor vehicle, which comprises a control device and a drive unit and is controlled by means of the control device, wherein n-dimensional reference input vectors (17, 18, 19, 20, 21, 22, 23, 24) are each assigned a reference output vector, which reference vectors are stored in the control device and from which an output vector can be determined at least for an n-dimensional input vector comprising operating parameters for the drive unit of the motor vehicle, characterised in that, when a new reference input vector with associated new reference output vector is present, the following steps are carried out in the specified sequence by means of the control device: a. Determining an individual error of the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24), which describes the accuracy with which the reference output vector of one of the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24) can be determined from the other reference input vectors (17, 18, 19, 20, 21, 22, 23, 24) and the reference output vectors assigned to them without having to refer to the one reference input vector (17, 18, 19, 20, 21, 22, 23, 24) and its reference output vector; b. Intermediate storage of the reference input vector (17, 18, 19, 20, 21, 22, 23, 24) with the smallest individual error and removal of this reference input vector (17, 18, 19, 20, 21, 22, 23, 24) from the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24); c. Calculating the output vector with the new reference input vector as the input vector; d. Determining the individual error from a difference between the output vector and the reference output vector assigned to the new reference input vector; e. Adding the removed reference input vector (17, 18, 19, 20, 21, 22, 23, 24) to the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24); f. Replacing the reference input vector (17, 18, 19, 20, 21, 22, 23, 24) with the smallest individual error by the new reference input vector if the individual error of the new reference input vector is greater than the smallest individual error; wherein g. the drive unit and the control device are supplied with the same input vector, which comprises the at least one operating parameter for the drive unit, wherein the drive unit is operated on the basis of the at least one operating parameter and the control device determines the output vector from the input vector, and wherein a measured value which is measured and which represents an output variable of the drive unit is compared with the output vector and, in the event of a deviation, a fault of the drive unit is recognised and/or the input vector is adapted in such a way that the measured value corresponds to the output vector. a. Determining an individual error of the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24), which describes the accuracy with which the reference output vector of one of the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24) can be determined from the other reference input vectors (17, 18, 19, 20, 21, 22, 23, 24) and the reference output vectors assigned to them without having to refer to the one reference input vector (17, 18, 19, 20, 21, 22, 23, 24) and its reference output vector; b. Intermediate storage of the reference input vector (17, 18, 19, 20, 21, 22, 23, 24) with the smallest individual error and removal of this reference input vector (17, 18, 19, 20, 21, 22, 23, 24) from the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24); c. Calculating the output vector with the new reference input vector as the input vector; d. Determining the individual error from a difference between the output vector and the reference output vector assigned to the new reference input vector; e. Adding the removed reference input vector (17, 18, 19, 20, 21, 22, 23, 24) to the reference input vectors (17, 18, 19, 20, 21, 22, 23, 24); f. Replacing the reference input vector (17, 18, 19, 20, 21, 22, 23, 24) with the smallest individual error by the new reference input vector if the individual error of the new reference input vector is greater than the smallest individual error; wherein g. the drive unit and the control device are supplied with the same input vector, which comprises the at least one operating parameter for the drive unit, wherein the drive unit is operated on the basis of the at least one operating parameter and the control device determines the output vector from the input vector, and wherein a measured value which is measured and which represents an output variable of the drive unit is compared with the output vector and, in the event of a deviation, a fault of the drive unit is recognised and/or the input vector is adapted in such a way that the measured value corresponds to the output vector.