Conditions for Running the DTC

WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

Before the ECM can report DTC P0328 or P0333 failed, DTC P0324, P0335, P0336 and P0338 must run and pass.
The engine is operating.
The engine speed is more than 2,000 RPM and steady.
The ECM is controlling spark.
The volumetric efficiency is steady.
DTC P0328 and P0333 run continuously once the above conditions are met for approximately 20 seconds.