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Diagnosis & Repair (Using Toyota Scan Tester)

  1. Connect scan tester. See Figure. Turn ignition on. Read EGR gas temperature. If temperature is 302°F (150°C), go to step 4). If temperature is not 302°F (150°C), go to next step. If temperature displayed is 318.7°F (159.3°C), there is a short in EGR temperature sensor circuit.
  2. Disconnect EGR temperature sensor connector. Using scan tester, read EGR gas temperature. If EGR gas temperature is not 37.6°F (3.1°C), go to next step. If 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 tester, read EGR gas temperature. If EGR gas temperature is 37.6°F (3.1°C), inspect and repair open in circuits between ECM and EGR temperature sensor. If temperature is not 37.6°F (3.1°C), replace ECM and retest.
  4. Using scan tester, select ACTIVE TEST mode. Check operation of VSV when activated by scan tester. Start and run engine. With EGR system off, air from port "E" should exhaust from filter on end of valve. See Figure. With EGR system on, air from port "E" should exhaust 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 an open circuit in wiring harness between VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
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