Initial Inspection and Diagnostic Overview

1. Visually inspect system components:
^ Loose, leaking, or damaged vacuum lines.
^ EGR valve stuck open.
^ EGR valve bolts loose or missing.
^ EGR valve flange gasket damaged or leaking.
^ Damaged electrical connectors or insulation.
^ Damaged components that affect EGR function.
^ Damaged EGR components.

2. Exercise EGR components wiring harness and connectors. Check for looseness, corrosion, or other damage. Do this with engine at operating temperature for activation of all EGR system components.
3. Check vacuum lines and connections for looseness, pinching, leakage, splitting, blockage, or liquid contamination.
4. If system inspection is okay, see PINPOINT TESTS.