A method for diagnosing contact pressure security in a continuously variable transmission having conical disk pairs and a contacting endless belt. Contact pressure forces between the disks and the belt are modified at a given transmission ratio, at a defined input and/or output torque, and at a contact pressure having a defined zeta ratio value between the contact pressure force on the input disk set and on the output disk set. The input and/or output torque is held constant. The resulting change of transmission ratio is determined, and based upon the transmission ratio change the contact pressure security is assessed based upon the deviation between the existing pressure security and an optimum pressure security.