Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2013 GMC Yukon XL, 2013 GMC Yukon, 2013 Chevrolet Suburban, 2013 Chevrolet Avalanche, and 2013 Cadillac Escalade EXT. However, it is still accessible from the selected car via links, so may be relevant.

The fuel tank vacuum is greater than 12 in H2O vacuum for 5 s before 10 L (2.6 gal) of purge volume.
OR
The fuel tank pressure (FTP) is less than -2.5 in H2O or more than +5 in for 60 s after a cold start.
After setting the DTC for the first time, 2 L (0.5 gal) of fuel must be consumed before setting the DTC for the second time.