Conditions for Setting the DTC: P2715
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The TCM detects an incorrect off-going clutch gear ratio, or tie-up, when the 2-6 clutch is commanded OFF for 0.5 seconds and the transmission input shaft speed is greater than 40 RPM from the anticipated input shaft speed.