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Home >> Lexus >> 1995 >> ES 300 >> Repair and Diagnosis >> External Pages >> Different car >> Section 12 (Engine Controls - Tests W/Codes - OBD-II) >> Diagnostic Testing >> Code P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 1995 Lexus LS 400. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tester to Data Link Connector (DLC) No. 3 connector. See Figure. Start engine and warm to normal operating temperature. Turn scan tester on. Monitor each oxygen sensor. Snap accelerate engine 3 times. Sensors should indicate a rich signal (.45 volts or more) at least once.
  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. Repair as necessary. If circuits are okay, replace oxygen sensor and retest.
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