Conditions for Running the DTC: Notes

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

P0451

DTC P0451 runs only when the engine-off natural vacuum small leak test, P0442, executes.
The number of times this test runs can range from 0-2 per engine-off period. The length of the test can be up to 10 minutes.