Exhaust Gas RECIRCULATION
WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For EGR system diagnosis, see appropriate INSPECTION/MAINTENANCE PROCEDURES under DRIVE CYCLES
in SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS article.