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Home >> Toyota >> 1997 >> T100 Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes - 2.7L >> Circuit Tests >> DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control >> Diagnosis & Repair
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Diagnosis & Repair

  1. Connect scan tool to DLC No. 3 connector. See Figure. Start vehicle and warm engine to normal operating temperature. Using scan tool, monitor output voltage of sensor No. 1. Snap accelerate engine 3 times. Sensor should indicate a rich signal (.45 volt or more) at least once.
  2. If a rich signal is indicated at least once, replace ECM and retest. If sensor does not display a rich signal at least once, check for open or short circuit in wiring harness between ECM and sensor. See appropriate wiring diagram in WIRING DIAGRAMS - 2.7L article. Repair wiring as necessary. If wiring harness is okay, replace oxygen sensor and retest.
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