Action Taken When the DTC Sets

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

DTC P1626 is a Type A DTC.
The TCM commands maximum line pressure.
The TCM turns off all solenoids - HSD1 and HSD2.
The TCM freezes transmission adaptive functions.
The TCM defaults the transmission to third gear if the current gear is 1st, 2nd, or 3rd; or fifth gear if the current gear is 4th, 5th, or 6th gear.
The TCM inhibits TCC.
The TCM inhibits Tap up and Tap down functions.