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Home >> Toyota >> 1996 >> Supra 3.0 D, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes - Non-Turbo >> Circuit Tests Non-Turbo >> DTC P0402 - Excessive Exhaust Gas RECIRCULATION (EGR) Flow Detected >> Diagnosis & Repair (Using OBD-II Scan Tester)
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Diagnosis & Repair (Using OBD-II Scan Tester)

  1. Disconnect EGR temperature sensor. Sensor is located on EGR valve assembly. Using ohmmeter, measure resistance between sensor terminals. If resistance is 2500 ohms or more, go to next step. If resistance is less than 2500 ohms, replace sensor.
  2. Inspect circuits between EGR temperature sensor and ECM for short. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuits are okay, go to next step.
  3. Remove EGR VSV. VSV is located near intake manifold at left front of engine. 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.
  4. Check VSV operation. Apply battery voltage to VSV terminals. Air from port "E" should exhaust from port "F". See Figure. Remove battery voltage from valve terminals. Air from port "E" should not pass from port "F". Replace VSV as necessary.
  5. If VSV meets all specifications in steps 3) and 4), check for a short circuit in wiring harness between EGR VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, replace ECM and retest.
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