Circuit/System Description
WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
The transmission control module (TCM) monitors the input speed sensor for excessive input shaft speed during an autostart event. The DTC will set if there is excessive input shaft speed indicating the accumulator system is not capable of supplying the necessary fluid pressure, to the clutches during autostart.