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Home >> Toyota >> 2000 >> RAV4 Base, AWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Control System Self-Diagnostics) >> Diagnostic Tests >> DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2000 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tool to Data Link Connector (DLC) No. 3. See Figure. Start and warm engine to normal operating temperature. Using scan tool, monitor heated oxygen sensor No. 1. Snap accelerate engine to about 4000 RPM 3 times. Heated oxygen sensor No. 1 should indicate a rich signal (.45 volt or more) at least once. If a rich signal is indicated for heated oxygen sensor No. 1 at least once, replace ECM. If heated oxygen sensor No. 1 does not display a rich signal at least once, go to next step.
  2. Check for open or short in wiring between heated oxygen sensor No. 1 and ECM. See WIRING DIAGRAMS article. If problem does not exists, go to next step. If problem exists, repair wiring as necessary.
  3. Using scan tool, check if a misfire has occurred by monitoring DTCs and DATA LIST. If a misfire has occurred, perform DTC P0300: RANDOM MISFIRE DETECTED . If misfire has not occurred, go to next step.
  4. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace defective heated oxygen sensor No. 1.
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