The existing problems of controlling the elevation position of a motor grader blade when leveling a roadbed, caused by arising measurement errors associated with both the operation of the control systems themselves and disturbing influences, are considered. It is shown that the optimally tuned regulators in the existing control system do not provide the required quality indicators for the operation of a construction machine. It is proposed to equip the automatic control system for the elevation position of the grader blade with an alternative position sensor, the signal from which is compared with the reference action and the difference is introduced as a correction to the control system. The developed system allows us to increase the accuracy of automatic elevation positioning of the motor grader blade up to the quality required by regulatory documents.