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Home >> Lexus >> 1996 >> LX 450 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0125 - Insufficient Coolant Temperature For Closed Loop Fuel Control >> Diagnosis & Repair

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. Sensors 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 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.
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