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Diagnosis & Repair (Using Toyota Scan Tool

  1. Connect scan tool. See Figure. Turn ignition on. Using scan tool, 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. Monitor 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 behind glove box. Disconnect ECM E7 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 EGR VSV when activated by scan tool. EGR VSV is located under throttle body. Apply air pressure to EGR VSV port "E". See Figure. With EGR system off, air from port "E" should flow from port "F". With EGR system on, air from port "E" should not flow from port "F". If VSV operates as specified, check EGR valve. See SYSTEM/COMPONENT TESTS - 2.4L article. If EGR VSV does not operate as specified, go to next step.
  5. Remove EGR VSV. Using ohmmeter, measure resistance between EGR VSV terminals. Resistance should be 33-39 ohms at 68°F (20°C). Check for continuity between each terminal and body of EGR VSV. If continuity exists, replace EGR VSV. If continuity does not exist, go to next step.
  6. Check EGR VSV operation. Apply battery voltage to EGR VSV terminals. Apply air pressure to EGR VSV port "E". Air from port "E" should flow from port "F". See Figure. Remove battery voltage from EGR VSV terminals. Air from port "E" should not flow from port "F". Replace EGR VSV as necessary. If EGR VSV operates as specified, go to next step.
  7. Check for open circuit in wiring harness between engine compartment fuse block and ECM. See appropriate wiring diagram in WIRING DIAGRAMS - 2.4L article. Repair wiring as necessary. If wiring harness is okay, replace ECM and retest.
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