A steering drive system for a steering system of a motor vehicle, comprising: - a first control device for actuating a first winding circuit of a steering drive motor with a test circuit which is designed to provide a defined alternating, in particular a periodic, test signal; - a second control device for actuating a second winding circuit of the steering drive motor, wherein a test signal receiving circuit of the second control device is designed to receive the test signal, wherein the second control device is designed to actuate the steering drive motor depending on the defined test signal, - wherein a position sensor for detecting the rotor position is provided, wherein the position sensor has a primary circuit via which, with the assistance of an actuation signal, a magnetic field is impressed in a soft magnetic element connected to a rotor of the steering drive motor, and has a secondary circuit which has at least one magnetic field sensor unit, - wherein the first and second control devices (110, 120) are connected to the position sensor in order to respectively receive position information, wherein the first and second control devices (110, 120) are designed to execute an actuation of the respective winding circuit (11a, 11b) depending on a determined position information, in particular by providing a rotor position-dependent commutation pattern, - wherein the first control device is designed to provide the actuation signal for the primary circuit of the position sensor, and wherein the first and second control device (110, 120) are connected to the at least one magnetic field sensor unit in order to detect the position information. - a first control device for actuating a first winding circuit of a steering drive motor with a test circuit which is designed to provide a defined alternating, in particular a periodic, test signal; - a second control device for actuating a second winding circuit of the steering drive motor, wherein a test signal receiving circuit of the second control device is designed to receive the test signal, wherein the second control device is designed to actuate the steering drive motor depending on the defined test signal, - wherein a position sensor for detecting the rotor position is provided, wherein the position sensor has a primary circuit via which, with the assistance of an actuation signal, a magnetic field is impressed in a soft magnetic element connected to a rotor of the steering drive motor, and has a secondary circuit which has at least one magnetic field sensor unit, - wherein the first and second control devices (110, 120) are connected to the position sensor in order to respectively receive position information, wherein the first and second control devices (110, 120) are designed to execute an actuation of the respective winding circuit (11a, 11b) depending on a determined position information, in particular by providing a rotor position-dependent commutation pattern, - wherein the first control device is designed to provide the actuation signal for the primary circuit of the position sensor, and wherein the first and second control device (110, 120) are connected to the at least one magnetic field sensor unit in order to detect the position information.