Conditions for Running the DTC: Notes

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

P0403, P0404, P0405, P0406, P042E

DTC P0641 or P0651 are not set.
The Ignition 1 Signal parameter is between 9-18 volts.
The engine is cranking or running.
These DTCs run continuously when the above conditions are met.

P0404

DTC P1258 is not set.
The EGR valve is commanded open.
The ECT is more than 75°C (167°F).