Component Tests and General Diagnostics

VACUUM CONTROLLED

1. Connect vacuum pump to two uppermost ports one at a time and check them for leakage.
2. When vacuum is applied to uppermost port and port immediately below that is open to atmosphere, uppermost port should open at 2.36 inches Hg.
3. When vacuum is applied to top two ports, they should both open at 19.69 inches Hg.
4. When two uppermost ports are open to atmosphere, valve should be closed.
5. If valve does not operate as described above, it should be replaced.

ELECTRONICALLY CONTROLLED

1. With engine off, inspect exhaust gas recirculation control valve for binding or sticking by moving valve diaphragm. Clean, correct or replace as necessary.
2. With engine running at operating temperature, check exhaust gas recirculation control valve operation when engine speed is raised from idling to 2000-4000 RPM.
3. If valve is malfunctioning make a thorough visual check of vacuum hoses for exhaust gas recirculation control system and replace or correct as necessary.
4. Apply vacuum to exhaust gas recirculation 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.