Conditions for Setting the DTC: P0506
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
The actual engine speed is less than the desired idle speed by at least 100 RPM for 4 seconds, or for a cumulative of 30 seconds.