LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2000 >> RAV4 Base, AWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics >> Diagnostic Tests >> DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control (Except CALIF. Emissions) >> Diagnosis & Repair
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis & Repair

  1. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0125 is displayed, go to next step.
  2. 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, go to step  10. If heated oxygen sensor No. 1 does not display a rich signal at least once, go to next step.
  3. Check for open or short in wiring between heated oxygen sensor No. 1 and ECM. If problem does not exist, go to next step. If problem exists, repair wiring as necessary. See WIRING DIAGRAMS article.
  4. 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.
  5. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
  6. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
  7. Check fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
  8. Check fuel injectors. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
  9. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace defective heated oxygen sensor No. 1.
  10. Perform test drive confirmation, then go to next step. See TEST DRIVE CONFIRMATION  under DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT (EXCEPT CALIF. EMISSIONS).
  11. Clear and recheck for DTCs. If DTC P0125 is displayed again, replace ECM. If DTC P0125 is not displayed again, go to next step.
  12. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.
scientia non olet · About LEMON Manuals