Theory Of Operation
WARNING: This page is about a different car, the 2015 Jeep Renegade. However, it is still accessible from the selected car via links, so may be relevant.
After the controller is reset, the microprocessor checks the integrity of each ROM location by writing to it and reading back from it. The read value should be the same as the written value. This is referred to as checksum. The MIL will illuminate and the transmission will be placed into limp-in after 10 seconds of problem identification.