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ok you to check for codes and due a vacuun test to check the diagram. Here is below how to do so far testing a possible causes.
Tests/Procedures: 1. Monitor the voltage on the EGR temperature sensor Green/White (GRN/WHT) wire. The voltage needs to drop below 1 volt when the EGR valve is operating. The voltage needs to drop fast, so the Engine Control Module (ECM) knows that the EGR flow is correct. 2. If the EGR temperature sensor voltage does not drop below 1 volt, or is slow to drop, verify that there is correct vacuum (4 to 7 inches) to the EGR valve while driving. 3. If the vacuum is correct, then check the EGR passages for carbon and verify that the EGR temperature sensors ground is good. If the voltage still will not drop, then check for a faulty EGR temperature sensor. 4. If all tests show that everything is working at this time, the EGR Vacuum Switching Valve (VSV) is common to fail intermittently and may need to be replaced.
Potential Causes: Exhaust Gas Recirculation (EGR) ModulatorRestricted Exhaust Gas Recirculation (EGR) PassagesExhaust Gas Recirculation (EGR) Temperature SensorExhaust Gas Recirculation (EGR) Vacuum Solenoid Valve (VSV)HarnessRestricted Vacuum Ports