Circuit Description
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) sends engine coolant temperature data to the transmission control module (TCM). The TCM uses this data to initiate warm-up shift patterns and to establish default transmission fluid temperature (TFT) values. The data is sent to the TCM through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the ECM and TCM. A fault in the CAN will not cause DTC P1792 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P1792.
When the TCM receives invalid engine coolant temperature data from the ECM, then DTC P1792 will set. DTC P1792 is a type A DTC.