Action Taken When the DTC Sets

WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

DTCs P0973 and P0974 are Type A DTCs.
The transmission control module defaults the transmission to EVT 1 or EVT 2 depending on vehicle speed.
The transmission control module commands maximum line pressure.
The transmission control module freezes transmission adaptive functions.