Theory Of Operation
WARNING: This page is about a different car, the 2019 RAM 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The purpose of the diagnostic is to detect an incorrect Transmission Control Module (TCM) configuration (calibration data) stored in the TCM. This diagnostic compares the Vehicle Identification Number (VIN) stored in the EEPROM of the TCM to the VIN received over the Controller Area Network (CAN).
When a new TCM is installed it receives the VIN information from the PCM. The TCM uses the VIN to know if the vehicle is configured as a Rear Wheel Drive (RWD) or Four Wheel Drive (4WD), single rear wheel or dual rear wheel and other information about the vehicle. One of the uses for this information is to correctly calculate torque management to prevent damage that could be caused by exceeding a components torque handling capability.