A drive train for a pivotable flap of a motor vehicle includes a holding device which can hold the flap in at least one open position, a first element which can be driven by a drive motor, and a second element connected to the pivotable flap to pivot the flap in response to movement of the first element. When the second element is moved along a path of motion relative to the first element counter to a specific spring force, a sensor generates a signal indicating relative motion of the elements, and a control device releases the holding device in response to the signal, whereby the flap can be moved manually by applying a force counter to the spring force.