Exhaust Gas Recirculation: Testing and Inspection

Modulator Check:

EGR MODULATOR

1. Remove vacuum hoses from modulator.
2. Place finger over modulator tubes "P" and "R" and blow in tube "Q." Air should pass through filter part of modulator.
3. Connect vacuum pump to tube "S" and plug tubes "P" and "R" with your finger.
4. Blow air into Tube "A." You should not be able to obtain vacuum on pump.
5. If EGR modulator fails this test, replace modulator.

Exhaust Gas Recirculation (EGR) Valve:

EGR VALVE

1. When Engine coolant temperature is above 60°C (158°F).
2. Place finger on EGR valve diaphragm and accelerate engine, the diaphragm should move.
3. Disconnect vacuum hose from EGR valve.
4. Apply 10" inches of vacuum using a vacuum pump to valve with finger on diaphragm. Diaphragm should move and engine should stumble and may stall.
5. If valve fails, replace valve.

Vacuum Solenoid Valve (VSV) Check:

EGR VACUUM SOLENOID VALVE (VSV) (California only)

1. Turn key "OFF."
2. Disconnect vacuum hoses from VSV.
3. Disconnect electrical connector.
4. Check resistance between terminals of VSV. Refer to SPECIFICATIONS for correct values.
5. Blow into tube "A," air should exhaust through filter, if not replace VSV, If OK proceed to step #6.
6. Reconnect electrical connector.

Diagnostic Connecter With Jumper Wire:

7. Turn key "ON," engine "OFF."
8. Ground diagnostic connector (as shown above).
9. Blow into tube "A," air should exhaust through tube "B," if not replace VSV.