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 engine speed information to the TCM via the Controller Area Network (CAN) bus. The ECM also determines if the engine RPM information is reliable or not, and sends that information to the TCM. DTC P0727 sets when the TCM receives an invalid engine speed signal from the ECM.