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Home >> Toyota >> 1996 >> Previa DX, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes >> Circuit Tests >> DTC 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 sensor No. 1. Snap accelerate engine 3 times. Sensor should indicate a rich signal (.45 volt or more) at least once. If a rich signal is indicated at least once, go to step 3). If sensor does not display a rich signal at least once, go to next step.
  2. Check for an open or short circuit between ECM and sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuits are okay, replace oxygen sensor and retest.
  3. Inspect all air induction components. Repair as necessary. If air induction components are okay, check fuel pressure. See BASIC TESTING article. Repair as necessary. If fuel pressure is okay, inspect fuel injectors. See SYSTEM/COMPONENT TESTS article. Replace injectors as necessary.
  4. If all injectors are okay, inspect Mass Airflow (MAF) sensor and Engine Coolant Temperature (ECT) sensor. See SYSTEM/COMPONENT TESTS article. Replace as necessary.
  5. If both components are okay, inspect ignition system. See IGNITION CHECKS in BASIC TESTING article. Repair as necessary. If ignition system is okay, check EVAP Vacuum Switching Valve (VSV). See SYSTEM/COMPONENT TESTS article.
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