[FRED]

Auto transmissions are not controlled from the stk ECU but from another computer called ECAT I believe. See the online FSM and the wiring schematics and the chapter on automatic transmissions plus the chapter on FUEL AND EMISSIONS which has the pinout for the stk ECU.

Attached is a jpg out of the series five wiring schematics that is one of three pages of ECAT inputs/output plus the book also shows the end points to and from the ECAT computer.