A method for operating a modular robot including a first module and a second module is provided. The first module includes a first controller, and the first controller includes a first failsafe position detection for a movable element of the first module. The method includes controlling the second module, which includes detecting a first position of movable elements via a first single position detector. A second position of the movable elements is detected via a second position detector, which is configured as a position probe that is attachable to the at least one movable element of the second module. The second position is combined with the first position to form a second failsafe position detection. The first failsafe position detection is combined with the second failsafe position detection to form a combined failsafe position detection for the modular robot.