Driver Shift Control (DSC)/Electronic Range Selection (ERS)
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
Refer to the owner's manual for specific instructions on DSC. The TCM will override shift commands when maximum engine speed is achieved and will protect from any downshift which may cause excessive engine RPMs.