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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. Sensor is located on EGR valve assembly. 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 behind glove box. Disconnect ECM E9 connector. See Fig 1. 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 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. VSV is located near intake manifold at left front of engine. Apply air pressure to VSV port "E". With EGR system off, air from port "E" should flow from port "F". See Figure. With EGR system on, air from port "E" should not flow from port "F". If VSV does not operate as specified, go to next step. If VSV operates as specified, check EGR valve. See SYSTEM/COMPONENT TESTS - NON-TURBO article.
  5. Remove EGR VSV. Using ohmmeter, measure resistance between valve terminals. Resistance should be 39-45 ohms at 68°F (20°C). Measure resistance between each terminal and body of valve. Resistance should be infinite. If resistance is not as specified, replace VSV. If resistance is as specified, go to next step.
  6. Check VSV operation. Apply battery voltage to VSV terminals. Apply air pressure to VSV port "E". Air from port "E" should flow from port "F". See Figure. Remove battery voltage from valve terminals. Air from port "E" should not flow from port "F". Replace VSV as necessary.
  7. If VSV meets all specifications in steps 5) and 6), check for a short circuit in wiring harness between EGR VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS - NON-TURBO article. Repair wiring as necessary. If wiring harness is okay, replace ECM and retest.
Fig 1: Identifying Engine Control Module (ECM) Connector Terminals
G97C06965Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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