Pinpoint Test H: DTCs C1278 and C1956 - Steering Angle Sensor Circuit Fault : Notes
WARNING: This page is about a different car, the 2008 Mercury Sable, 2008 Ford Taurus X, and 2008 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
Refer to appropriate SYSTEM WIRING DIAGRAMS article, Vehicle Dynamic Systems for schematic and connector information.