EGR System Control Test

1. With engine off, inspect EGR control valve for binding or sticking by moving valve diaphragm. Clean, correct, or replace as necessary.
2. With engine running at operating temperature, check EGR control valve operation when engine speed is raised from idling to 2000-3000 RPM.
3. If valve is malfunctioning, make a thorough visual check of vacuum hoses for EGR control system and replace or correct as necessary.
4. Apply vacuum to EGR control valve and check that it moves to full-up position. Plug hose with applied vacuum. Valve should remain open for at least 30 seconds. If not, replace valve.
5. Disconnect an EGR solenoid valve connector and remove vacuum hose between VCM and EGR control valve.
6. Using vacuum gauge, check vacuum with battery voltage applied to connector. Switch should come on at .39-.79 inch Hg and should shut off at about 4.72 inches Hg. If valve does not operate to specifications, replace VCM.
7. Check system wiring.
8. Disconnect 20-pin connector and measure resistance between terminal 4 and ground. If resistance is 38-42 ohms, replace control unit.
9. If resistance is not 38-42 ohms, disconnect connector of VCM solenoid valve for EGR control and check resistance between each terminal of connector.
10. If resistance is now 38-42 ohms, check harness and repair or replace as necessary.
11. If resistance is not 38-42 ohms, replace VCM.