Conditions for Running the DTC

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

DTCs P0450, P0451, P0452, and P0453 are not set.
The barometric pressure (BARO) indicates that the altitude is less than 2,400 meters (7,872 feet).
The battery voltage is at least 11 volts.
The fuel level is approximately 10-90 percent-no excess fuel slosh is indicated.
The engine coolant temperature (ECT) sensor and the intake air temperature (IAT) sensor are near the same temperature at engine start.
The ECT and the IAT are between 10°C (50°F) and 32°C (89°F) at engine start.
The engine has been operating for at least 50 minutes.
The vehicle is operated at steady speeds.
The EVAP canister purge valve has been open and the fuel tank pressure (FTP) sensor indicates a negative pressure in the fuel tank of at least -18 mm Hg (-9.63 inches H2O).
DTC P0442 runs once per drive cycle when the above conditions are met.