This type of automatic repair controls actuators in such a way that by adjusting parameters SMM tries to recover part of its requested functions. Some part of these functions might be lost or degraded, but important functions need to be maintained, e.g. functional trade-off. For example, in the copier, when the halogen lamp brightness decreases the transfer charger controller can be used to adjust brightness of the image. In this sense, the state of the machine is unchanged, e.g., everything is functioning albeit at different settings. The latter is the usual repair mechanism, e.g. including additional redundant parts.
Functional redundancy uses potential functions of parts in a different way from the original design.
One example is the use of the starting motor of an automobile to generate driving force in an emergency situation. In the context of a copier, a function might be to charge the drum, normally done by the main charger. But copiers also have a second charger, the transfer charger whose main function is to transfer toner from the drum to the output paper. If the main charger fails the transfer charger can be engaged to charge the drum in addition to its primary function to transfer toner. For this to work it is necessary not only to have the sensor data, but perhaps more importantly to have a model of what the machine is supposed to do, and how parameter changes affect machine functions.