Circuit Description
WARNING: This page is about a different car, the 2003 Saturn Vue and 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The ECM sends serial data to the TCM via the Controller Area Network (CAN) bus. DTC 1780 does not indicate a problem with the transaxle or with the TCM. It does indicate that the ECM is not sending the required information to the TCM. Check for any related DTCs stored in the ECM and the Electronic Brake Traction Control Module (EBTCM). Clear DTCs in the TCM after a repair is made to the engine or anti-lock brake system.