Conditions for Setting the DTC: P2669
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.
This DTC sets when the HSD2 voltage is greater than 6 V and the TCM detects an open circuit on 2 or more of the solenoids (SS1, SS2, SS3, or PCS2) connected to the HSD2.