System Operational Test

The following procedures will allow a basic operational test of the EGR system. Since the EGR operation is controlled by the ECU, refer to COMPUTERIZED ENGINE CONTROLS for further information concerning testing of the systems operation.

EGR System Inspection:

1. Disconnect the vacuum hose (green stripe) from the throttle body and connect a vacuum pump to the free end of the hose.
2. While the engine is cold (coolant temperature less than 50 degrees C or 122 degrees F) apply vacuum at idle and note that vacuum leaks.
3. Allow the engine to warm up (coolant temperature greater than 85 degrees C or 185 degrees F).
4. Apply 45 mm Hg or 1.7 in. Hg of vacuum while the engine is at idle and note that vacuum is held.
5. Apply 215 mm Hg or 8.5 in. Hg of vacuum while the engine is at idle and note that the idle becomes unstable.