Theory Of Operation
WARNING: This page is about a different car, the 2013 Jeep Patriot and 2013 Jeep Compass. However, it is still accessible from the selected car via links, so may be relevant.
The Transmission Control Module monitors and controls the gear ratio by the use of a Step motor that transfers electrical power to mechanical movement. The rationality is a continuous test that monitors the Step motor movement. If the Step motor ON/OFF status does not match the TCM requested ON/OFF status a DTC will set.