Theory Of Operation

The Electronic Shift Module (ESM) can communicate with the Transmission Control Module (TCM) on the Controller Area Network (CAN) or the Dedicated Powertrain (D-PT) CAN bus. If the ESM loses communication with the TCM on the CAN C bus it will continue to communicate on the D-PT CAN bus and set a DTC against the TCM for CAN C bus off. If the ESM loses communication with the TCM on the CAN-DPT bus it will continue to communicate with the CAN C bus and set a DTC against the TCM for D-PT CAN bus off.