Method and control device for operating a drive train

A method for operating a drive train of a motor vehicle, drive train comprising a drive aggregate, a drive output, an automated group transmission connected between the drive aggregate and the drive output, and a disconnect clutch connected between the drive aggregate and the group transmission, wherein the group transmission comprises a plurality of sub-transmissions that include at least one of (i) a main transmission and a splitter group drivingly connected upstream from the main transmission and (ii) a range group drivingly connected downstream from the main transmission, wherein when the disconnect clutch cannot be used to carry out a shifting operation in the group transmission, namely it cannot be shifted, an emergency shifting program is activated,

• closing the disconnect clutch;
• and
• shifting automatically, according to an emergency shifting program, from a current gear to a target gear of the group transmission, wherein the emergency shifting program is performed as a function of an input rotation speed of the group transmission or as a function of a rotation speed of the drive aggregate;
• wherein the main transmission and/or the range group participate exclusively in the shifting.