Exhaust Gas Recirculation: Testing and Inspection

SYSTEM INSPECTION

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

1. Start the engine.

Fig. 144 EGR Valve:

2. Accelerate the engine and check that the diaphragm of the EGR control valve does not move while the engine is still cold.
3. Warm up the engine to normal operating temperature and run it at idle.

WARNING: Be careful when checking because the surrounding area is very hot!

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

SOLENOID VALVE (EGR, VACUUM SIDE)

Fig. 142 Solenoid Test Vac Side:

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

SOLENOID VALVE (EGR, VENT SIDE)

Fig. 143 Solenoid Test Vent Side:

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


EGR CONTROL VALVE

NOTE: If the engine will not start (cranks OK), perform only step 1.

1. Check that the EGR control valve rod slides smoothly by a hand.

Fig. 145 EGR Test:

2. Disconnect the vacuum hose from the EGR control valve, and connect a vacuum pump to the valve.
3. Start the engine, and run it at idle; then apply vacuum.
4. Check that the engine runs roughly or stalls at more than 40-60 mmHg (1.6-2.4 in.Hg) of applied vacuum.
5. If not correct, replace the EGR control valve.