P0601, P0604

WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

DTCs P0601, P0604 are Type A DTCs.
The TCM commands soft landing to second gear.
The TCM commands maximum line pressure.
The TCM forces the TCC OFF.
The TCM freezes transmission adaptive functions.