Conditions for Setting the DTC: P2723
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.
During a shift with PCS1 controlling the oncoming clutch, the TCM detects that the calculated commanded gear ratio differs from the known commanded gear ratio for 2 seconds.