Exhaust Gas Recirculation: Testing and Inspection

1. Check vacuum hose routing. If hose is improperly connected, clogged or leaking, repair or replace as necessary.
2. Warm engine to normal operating temperature and run at idle.
3. Disconnect vacuum hose from top of EGR control valve and plug hose. If engine roughens, check EGR control valve.
4. Unplug hose and connect a suitable vacuum gage to it.
5. Disconnect hose from bottom of EGR modulator valve and plug hose.
6. Connect suitable hose to vacant port of EGR modulator valve.
7. Increase engine speed to 2500 RPM and blow air into connected hose. If vacuum does not increase, check EGR modulator valve.
8. Restore vacuum hoses to original position.
9. Disconnect remaining hose from EGR modulator valve and connect suitable vacuum gage to hose.
10. Increase engine speed to 2500 RPM. If vacuum is not greater than 5.9 inches Hg, check three-way solenoid valve.
11. Disconnect water temperature switch electrical connector and increase engine speed to 2500 RPM.
12. If gage shows vacuum, check three-way solenoid valve and terminal 2N of EGI control unit.