EGR Function Testing - Gasoline: Other Chevrolet RV Cutaway G30

Vacuum Modulated (Ported) & Negative Backpressure Types

1. Turn engine off. Disconnect vacuum hose from EGR valve. Place finger underneath valve and push up to depress valve diaphragm. With diaphragm depressed, plug vacuum port on EGR valve.
2. Diaphragm should take over 20 seconds to return to its seated position. If diaphragm takes less than 20 seconds to return to its seat, replace EGR valve.
3. Depress diaphragm and plug vacuum port. Immediately start engine and observe diaphragm movement. Diaphragm is operating properly if diaphragm moves to seated position during cranking and initial starting.
4. If diaphragm does not move during cranking or initial starting, EGR valve should be cleaned.