Action Taken When the DTC Sets

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

P0776 or P0777

DTCs P0776 and P0777 are Type A DTCs.
If the transmission was in a forward gear, the transmission will shift back to the previous gear. If the transmission was in reverse or neutral, the transmission will shift to neutral.
The TCM inhibits torque converter clutch (TCC) engagement.