Conditions for Setting the DTC
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0847 sets when shift solenoid 2 (SS2) is commanded OFF and PS2 status remains ON for 2-16 seconds, depending on fluid temperature.