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.
This diagnostic checks the validity of the two CAN messages sent by the Powertrain Controller Module (PCM) containing information about the engine torque. The diagnostic checks the validity by performing a CRC and message counter check to be sure the CAN messages are continuously updated by the PCM and they contain valid values.