EGR Control Solenoid: Testing and Inspection

1. Connect ECU test harness to ECU.
2. Disconnect EGR VSV rubber hose.
3. Connect a MityVac vacuum pump or equivalent to the modulator side port of EGR VAV and apply vacuum. If able to produce vacuum, replace the EGR VSV.
4. Attach vacuum pump to the surge tank side port of EGR VSV and apply vacuum of 3.94 inches.
5. Turn ignition switch on. Vacuum should bleed off and vacuum pump should read zero.
6. If vacuum fails to bleed off, ensure voltage is applied to terminals 18 and 39 of the ECU test harness. If voltage is not present perform ECU test as outlined under ``System Diagnostic Check.''
7. If voltage is present check EGR VSV terminals. Resistance of EGR VSV is 30-50 ohms.
8. Start engine and proceed as follows:
a. When coolant temperature is below 104°F, connect a vacuum pump to surge tank port. Ensure vacuum is present.
b. If no vacuum is present, ensure proper operation of water temperature sensor.
c. When coolant temperature is above 104°F, connect a vacuum pump to surge tank port. Apply vacuum.
d. Ensure engine malfunctions or stall when vacuum is applied.
e. If engine continues to run and does not show signs of malfunction, ensure proper operation of water temperature sensor and EGR system.
9. Reconnect original vacuum hose to EGR VSV.
10. When coolant is below 104°F, start engine. While engine is running measure voltage between ECU test harness terminals 18 and 39.
11. Voltage should drop as engine warms up.
12. If voltage does not drop, check and repair water temperature sensor system. If water temperature sensor system is functioning normally, perform ECU test as outlined under ``System Diagnostic Check.''
13. Perform EGR VSV circuit test.

Fig. 53 ECU System Diagnosis, EGR VSV Check: