Conditions for Setting the DTC

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The ECM detects that the FTP is less than -16.4 mm Hg (-8.8 in. H2O) with EVAP vent solenoid valve commanded OFF.
The condition is present for greater than 4 seconds.