Exhaust Gas Recirculation: Testing and Inspection

EGR System Inspection (Federal):

EGR SYSTEM INSPECTION (FEDERAL VEHICLES)

1. Disconnect the green striped vacuum hose from the throttle body and connect a hand vacuum pump to the disconnected vacuum hose.
2. Plug the nipple the vacuum hose was disconnected from.
3. While the engine is cold (coolant temperature less than 40 degrees C or 104 degrees F) and the engine operating at idle apply vacuum and verify that vacuum leaks.
4. Warm up the engine (coolant temperature greater than 80 degrees C or 176 degrees F).
5. While the engine is idling apply 44 mm Hg or 1.8 in. Hg and verify that vacuum is held.
6. Increase vacuum to 215 mm Hg or 8.5 in. Hg and verify that vacuum is held and engine idle becomes unstable.

EGR System Inspection:

EGR SYSTEM INSPECTION (CALIFORNIA VEHICLES)

1. Disconnect the green striped vacuum hose from the EGR valve and connect a hand vacuum pump through a vacuum "Tee".
2. While the engine is cold (coolant temperature less than 20 degrees C or 68 degrees F) race the engine and verify that vacuum is not present.
3. Allow the engine to warm up (coolant temperature greater than 70 degrees C or 158 degrees F).
4. Race the engine and verify that vacuum increases to 100 mm Hg or 3.9 in. Hg or more.

EGR Valve Inspection:

5. Disconnect the vacuum "Tee" and connect the vacuum pump directly to the EGR valve.
6. Using the vacuum pump apply 215 mm Hg or 8.5 in. Hg of vacuum while the engine is at idle and verify that idle becomes unstable.

EGR Voltage Test:

7. Disconnect the yellow/green striped hose from the solenoid valve and connect a hand vacuum pump to the fitting.
8. Disconnect the electrical connector.
9. Apply battery Voltage to the electrical connectors as shown.
10. Apply vacuum to the solenoid with the pump and note the results.
a. Vacuum should hold when Voltage is applied.
b. Vacuum should NOT hold when NO Voltage is applied.

EGR Resistance Test:

11. Using an ohm meter check the resistance across the solenoid terminals.

Resistance:
36 - 44 Ohms @ 68° F.