I have been fighting a shift problem since I got my truck running. 2007 5.3 w/ 4L65E. I have an External speedo cable driven VSS that is wired per the schematic directly to pin 16 and 41 on the TCM.
The ECM schematic shows the same two wires (circuit 821 and 822) on pins 71 and 72 connecting to "transmission system".
I understand how the signal gets from the VSS to the TCM (it's wired directly to it) but there is no TCM out to ECM for the VSS???
Can anyone tell me from the attachment how the VSS signal gets to the ECM?