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Home >> Lexus >> 1997 >> SC 400 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0402 - Excessive EGR Flow Detected >> Diagnosis & Repair (Using OBD-II Scan Tool)
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Diagnosis & Repair (Using OBD-II Scan Tool)

  1. Check EGR temperature sensor. See ENGINE SENSORS & SWITCHES in SYSTEM/COMPONENT TESTS article. Replace sensor as necessary. If sensor is okay, go to next step.
  2. Check for open or short circuit in wiring harness between EGR temperature sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If wiring harness is okay, go to next step.
  3. Check EGR valve. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article. Replace EGR valve as necessary. If EGR valve is okay, replace ECM and retest.
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