Theory Of Operation
WARNING: This page is about a different car, the 2012 Jeep Patriot and 2012 Jeep Compass. However, it is still accessible from the selected car via links, so may be relevant.
The Transmission Control Module (TCM) calculates the checksum in the EEPROM and compares it to the stored checksum value. If the calculated checksum value does not match the stored checksum value the TCM sets the DTC and illuminates the MIL.