DTC P0973: Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1); DTC P0974: Shift Solenoid "A" Control Circuit High (Shift Solenoid Valve S1): Wiring Diagram
WARNING: This page is about a different car, the 2011 Toyota Matrix. However, it is still accessible from the selected car via links, so may be relevant.