Theory Of Operation
WARNING: This page is about a different car, the 2017 Jeep Patriot and 2017 Jeep Compass. However, it is still accessible from the selected car via links, so may be relevant.
During the initial ignition on, the Transmission Control Module (TCM) receives the calibrated data from the Engine/Powertrain Control Module (ECM/PCM) over the CAN Bus and stores this information in the EEPROM of the TCM. During normal operation the TCM compares the stored data in the EEPROM to the transmitted data from the ECM/PCM. If the calibration data does not match the DTC will set and the MIL will illuminate after two consecutive failures.