Using integrated multi-component assembly injection moulding, a two-part magnetic rotational angle sensor system having high sensing accuracy is very efficiently integrally produced in a tool as a functional unit that can be directly applied, comprising a polymer-bonded permanent magnet as a passive transmitter part in the first section, which can be rotated relative to the material of the active sensor receiver part, which material is sprayed thereon and then shrunk, with the potted receiver. For this purpose, injection moulding materials are used that are mutually incompatible for adhesion and lift off from one another over the mutual contact regions due to shrinkage.