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Home >> Lexus >> 1995 >> LS 400 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - OBD-II >> Diagnostic Testing >> Code P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Connect scan tester to Data Link Connector (DLC) No. 3 connector. See Figure. Start engine and warm to normal operating temperature. Turn scan tester on. Monitor each oxygen sensor. Snap accelerate engine 3 times. Sensors should indicate a rich signal (.45 volts or more) at least once.
  2. If a rich signal is indicated for both sensors, replace ECM and retest. If either sensor does not display a rich signal, inspect circuits between ECM and suspect sensor for open or short circuits. Repair as necessary. If circuits are okay, replace oxygen sensor and retest.
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