A method for monitoring an actuator device of a reciprocating piston engine, wherein the actuator device is designed to actuate, particularly reversibly displace, a sliding cam device of the reciprocating piston engine, particularly substantially parallel to a camshaft of the reciprocating piston engine, with the steps S1 Feeding of actuation energy to the actuator device, whereupon the actuator device undergoes a first state change, S2 Monitoring of the actuator device and detection of a second state change of the actuator device, S3 Determining of a first angle of rotation α of a camshaft or of the camshaft of the reciprocating piston engine on the basis of the second state change.