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Home >> Toyota >> 1997 >> Avalon XL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes >> Circuit Tests >> DTC P0402: Excessive Exhaust Gas RECIRCULATION (EGR) Flow Detected >> Diagnosis & Repair (Using Toyota Scan Tool)
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Diagnosis & Repair (Using Toyota Scan Tool)

  1. Using scan tool, select ACTIVE TEST mode. Check operation of VSV when activated by scan tool. VSV is located under "V" bank cover on top of engine. Apply air pressure to VSV port "E". With EGR system off, air from port "E" should flow from port "G". See Figure. With EGR system on, air from port "E" should flow from port "F". If VSV operates as specified, go to step 4). If VSV does not operate as specified, go to next step.
  2. Remove EGR VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 27-33 ohms at 68°F (20°C). Measure resistance between each terminal and body of VSV. Resistance should be infinite. If resistance is not as specified, replace VSV. If resistance is as specified, go to next step.
  3. Check VSV operation. Apply battery voltage to VSV terminals. Apply air pressure to VSV port "E". Air should flow from port "F". Remove battery voltage from VSV terminals. Air should flow from port "G". Replace VSV as necessary. If VSV meets all specifications in steps 2) and 3), check for a short in EGR VSV circuits between EGR VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
  4. Disconnect vacuum hose from EGR valve. Connect a vacuum pump to EGR valve. Start engine. Apply vacuum to EGR valve. If engine does not run rough or stall, replace EGR valve and retest. If engine runs rough or stalls, check EGR valve position sensor. See SYSTEM/COMPONENT TESTS article. Replace EGR valve position sensor as necessary. If EGR valve position sensor is okay, replace ECM and retest.
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