respectively during the opening or respectively closing of the valve element 10 and determines a deviation u03b1 1 between actual and required position if for example for the configuration of a camshaft adjustment characteristic map or of the camshaft adjustment device 31 an opening or respectively closing is provided at a particular camshaft required position u03b1 n d and if the ecu 40 detects this opening or respectively closing instead at a camshaft actual position u03b1 n i then it determines at s 40 as a difference u03b4 1 u03b1 n d u2212 u03b1 n i if the difference u03b4 1 is therefore for example greater than zero the valve element opens or respectively closes too early or respectively at an earlier position of the crankshaft 30 at s 50 the ecu 40 checks in an analogous manner whether the sensor s 3 has detected a start of a further opening process of the valve element 10 in a modification the ecu 40 can also check again at s 50 whether the sensor s 3 has detected an end of a further closing process of the valve element 10 likewise the ecu 40 can also check at s 50 whether the sensor s 4 on the basis of corresponding force values detected by the sensor s 4 has detected a start of a further opening process or an end of a further closing process of the valve element 10 likewise at s 50 the ecu can also check whether the sensor s 3 u2032 has.