Circuit Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
Engine speed information is sent to the transmission control module (TCM) by the engine control module (ECM) through the controller area network (CAN). A 2-wire circuit is used to communicate data between the ECM and TCM, CAN H and CAN L. A fault in the CAN will not cause DTC P0727 to set by itself. If a communication fault occurs, other DTCs will set before P0727.
When the ECM sends the TCM an invalid engine speed, DTC P0727 sets. DTC P0727 is a type B DTC.