Conditions For Running DTC

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Cab & Chassis Sierra. However, it is still accessible from the selected car via links, so may be relevant.

DTCs P0461, P0462, P0463, P1431, P1432, P1433 are not set.
The vehicle speed is 0 MPH.
The engine has been idling for more than 2 minutes and 20 seconds.
The primary fuel level is less than 15.8 gal. (60 L).
The secondary fuel level is more than 2.6 gal. (3 L).
The above conditions are met for 20 seconds before the secondary pump is commanded ON.
The secondary fuel pump is commanded ON for 120 seconds.