Circuit/System Verification
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.
With the ignition ON and the engine OFF, command the EGR from 0-100 percent. The EGR Position Sensor parameter should remain within 3 percent of the Desired EGR Position parameter.