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Diagnosis & Repair (Using Toyota Scan Tool)

  1. Connect scan tool. See Figure. Turn ignition on. Read EGR gas temperature. If EGR gas temperature is 302°F (150°C), go to step 4). If EGR gas temperature is not 302°F (150°C), go to next step.
    NOTE: If EGR gas temperature displayed is 318.7°F (159.3°C), a short exists in EGR temperature sensor circuit.
  2. Disconnect EGR temperature sensor connector. Using scan tool, read EGR gas temperature. If EGR gas temperature is not 37.6°F (3.1°C), go to next step. If EGR gas temperature is 37.6°F (3.1°C), replace sensor and retest.
  3. Turn ignition off. Access ECM under driver's seat. Disconnect ECM E6 connector. See Figure. Turn ignition on. Using scan tool, read EGR gas temperature. If EGR gas temperature is 37.6°F (3.1°C), locate and repair open circuit in wiring harness between ECM and EGR temperature sensor. If EGR gas temperature is not 37.6°F (3.1°C), replace ECM and retest.
  4. Using scan tool, select ACTIVE TEST mode. Check operation of VSV when activated by scan tool. Start and run engine. With EGR system off, air from port "E" should flow from filter on end of valve. See Figure. With EGR system on, air from port "E" should flow from port "F". If VSV operates correctly, check EGR valve. See SYSTEM/COMPONENT TESTS article. If VSV does not operate correctly, go to next step.
  5. Remove EGR VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 37-44 ohms at 68°F (20°C). Check for continuity between each VSV terminal and body of valve. If continuity exists, replace VSV. If continuity does not exist, go to next step.
  6. Check for short circuit in wiring harness between VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM and retest.
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