Conditions for Running the DTC: P0451

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

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.