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Home >> Toyota >> 1995 >> Tercel Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> 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 front oxygen sensor. Snap accelerate engine 3 times. Sensor should indicate a rich signal (.45 volt or more).
  2. If a rich signal is indicated for sensor, replace ECM and retest. If 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 article. Repair as needed. If circuits are okay, replace oxygen sensor and retest.
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