Exhaust Gas Recirculation System

EGR System:

EGR VALVE TESTING

1. Disconnect vacuum hose from valve and attach hand vacuum pump.
2. Apply 100 mmHg (3.9 in.Hg) vacuum.
3. The diaphragm should not leak down and should move to the fully up position.
4. Replace the EGR valve if it fails this test.

Back Pressure Transducer Testing:

BACK PRESSURE TRANSDUCER (BPT) TESTING

1. Plug one vacuum port.
2. Connect vacuum pump to the other vacuum port.
3. Connect 24" clear tubing to the exhaust gas port.
4. While holding clear tubing as shown in diagram, fill a portion of the tubing with water so that the level of water in the open end is approximately 3" higher than the level in the side connected to the valve (distance "A" in diagram.) Be sure there is an air space in the closed end to prevent water from getting into the BPT.
5. Apply approx. 50mmHg (2 in.Hg) vacuum with the vacuum pump. Vacuum should hold without leaking down.
6. Lower open end of tubing slowly. When distance "A" is less than approximately 2", air should be allowed into the transducer BPT (vacuum as shown on vacuum pump gauge should go to zero.)
7. Replace if defective.

Thermal Vacuum Valve:

THERMAL VACUUM VALVE (TVV) TESTING

1. Remove TVV from vehicle.
2. Check that no air passes between the vacuum ports when TVV is cold (below 46~-54~C, 115~-129~F).
3. Immerse thermo-sensing portion of TVV in hot water (at least 60~C).
4. Check that the TVV opens and air will pass between the ports within three minutes of being placed in the hot water.
5. Replace TVV if it fails this test.

EGR TEMPERATURE SENSOR (CALIFORNIA ONLY)

If a malfunction in the EGR temperature sensor occurs, the ECM will set a code 32 or 34. For detailed EGR temperature sensor testing procedure, see COMPUTERIZED ENGINE CONTROLS. For a resistance test, proceed as follows:
1. Remove EGR temperature sensor from vehicle.
2. Immerse sensing end in a pan of oil.
3. Connect an ohmmeter across sensor electrical terminals and use an appropriate thermometer to measure oil temperature.
4. Heat oil and compare temperature and ohmmeter readings with chart.
5. If measured resistance deviates from the specified range, replace EGR temperature sensor.

Temperature ~C(~F) Approx. K Ohms

0 (32) 28.0
20 (68) 12.1
40 (109) 5.8
80 (176) 1.7