Conditions for Setting the DTC

WARNING: This page is about a different car, the 2007 Isuzu i-370, 2007 GMC Canyon, and 2007 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.

The control module detects a pressure change that is less than a calibrated amount.
A minimum of 3 failed tests are required for the powertrain control module (PCM) to report a fail.
One test occurs at ignition OFF after a drive cycle, and may require up to 45 minutes to complete. No more than 2 tests per day are allowed. Five to 12 tests must be completed to report a fail.