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Home >> Toyota >> 1995 >> T100 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.7L >> Diagnostic Testing >> Code P0125 - Insufficient Coolant Temperature For Closed Loop Fuel Control >> Diagnosis & Repair
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Diagnosis & Repair

  1. Connect scan tester to DLC3 connector. See Figure. Start vehicle and warm engine to normal operating temperature. Turn on scan tester. Monitor each oxygen sensor. Snap accelerate engine 3 times. Sensors should indicate a rich signal (.45 volt or more).
  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. See wiring diagram in the WIRING DIAGRAMS - 2.7L article. Repair as needed. If circuits are okay, replace oxygen sensor and retest.
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