EGR Vent/EGR Solenoids
WARNING: This page does not describe the selected car, but rather 33 other vehicles, including the 2002 Saturn Vue, 2002 Pontiac Montana, 2002 Pontiac Aztek, 2002 Oldsmobile Silhouette, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.
EGR vent/EGR solenoids are mounted at rear of engine as a single assembly. Using input from engine speed sensor and Accelerator Pedal Position (APP) sensor, PCM controls EGR by controlling amount of "on" and "off" time of EGR solenoid. When EGR is not needed, PCM energizes EGR vent solenoid to vent vacuum. Vacuum is used to control EGR valve opening.