Conditions for Running the DTC

WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0641 and P0651 are not set.
The Ignition 1 Signal parameter is more than 11 volts.
The engine is running.
The DTC P0401 intrusive test is not active.
The EGR valve is not being commanded with a scan tool.
The EGR command will be disabled if the start-up engine coolant temperature (ECT) is less than 5°C (41°F) and will not enable until the ECT Sensor parameter is more than 75°C (167°F).
DTC P0406 runs continuously when the above conditions are met.