Exhaust Gas Recirculation: Testing and Inspection

SYSTEM INSPECTION

Fig. 144 EGR Valve:

NOTE: Check condition of wiring harness and/or vacuum lines and connectors before checking sensors or switches.

1. Start engine.
2. Accelerate engine and check that EGR valve diaphragm does not move while engine is still cold.
3. Warm engine to operating temperature and run at idle.

WARNING: Be careful when checking. Surrounding area is hot.

4. Accelerate engine and check that EGR valve diaphragm moves upward.

SOLENOID VALVE (EGR, VACUUM SIDE)

Fig. 142 Solenoid Test Vac Side:

1. Disconnect vacuum hoses.
2. Blow through hose and make sure air does not flow.
3. Disconnect valve connector.
4. Apply 12V and ground to valve as shown.
5. Blow through hose and make sure air flows.
6. If not correct, replace valve.

SOLENOID VALVE (EGR, VENT SIDE)

Fig. 143 Solenoid Test Vent Side:

1. Disconnect vacuum hoses.
2. Blow through hose and make sure air flows.
3. Disconnect valve connector.
4. Apply 12V and ground to valve as shown.
5. Blow through hose and make sure does not flow.
6. If not correct, replace valve.

EGR CONTROL VALVE

Fig. 145 EGR Test:

1. Check that valve rod slides smoothly by a hand.
2. Disconnect vacuum hose from valve and connect a vacuum pump.
3. Start engine, run it at idle, and apply vacuum.
4. Check that the engine runs roughly or stalls at more than 1.6 - 2.4 inHg (40-60 mmHg) of vacuum.
5. If not correct, remove EGR valve and check for carbon plugging passages. If not plugged, replace valve.