Control device for gear shifting device, control system for gear shifting device, and external arithmetic operation device

A control device for a gear shifting device, the gear shifting device applied to a vehicle and including frictional engagement elements and being configured to automatically change a gear shift ratio between an onboard motor and driving wheels, the control device comprising an electronic control unit configured to perform:

• an abnormality determining process of determining whether an abnormality of the gear shifting device has occurred;
• a fail-safe process of switching a frictional engagement element among the frictional engagement elements corresponding to the abnormality to a disengaged state and fixing the gear shift ratio of the gear shifting device when it is determined in the abnormality determining process that the abnormality has occurred;
• a relief determining process of determining whether the abnormality has been relieved based on a behavior of an input signal at a time of operating a drive device of the frictional engagement element corresponding to the abnormality on condition that the frictional engagement element is maintained in the disengaged state after it is determined in the abnormality determining process that the abnormality has occurred;
• and
• a release process of releasing the fail-safe process when it is determined in the relief determining process that the abnormality has been relieved.