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Home >> Cadillac >> 2000 >> Seville SLS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 4.6L >> Diagnostic Tests >> DTC P0125: ECT Excessive Time To Enter Closed Loop Fuel Control >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Turn engine off and allow to cool completely. Start and operate engine at idle. Using scan tool, monitor ENG COOL TEMP display. If ECT reading increases to greater than 68°F (20°C) within 2 minutes, see DIAGNOSTIC AIDS . If ECT reading does not increase to greater than 68°F (20°C) within 2 minutes, go to next step.
  3. Check if DTC P0117, P0118, P1114 or P1115 is set. If any of these DTCs are set, diagnose affected DTC(s) first. If any of this DTC is not set, go to next step.
  4. Allow engine to cool down. Turn ignition on. Observe cooling fans. If cooling fans are off, go to next step. If cooling fans are on, diagnose electric cooling fan. See appropriate ELECTRIC COOLING FANS article in ENGINE COOLING.
  5. Check coolant level. If coolant level is okay, go to next step. If coolant level is not okay, go to step  9.
  6. Compare engine coolant temperature displayed on scan tool to actual coolant temperature measured with a thermometer. If temperatures are within plus or minus 5°F (3°C), go to step  8. If temperatures are not within plus or minus 5°F (3°C), go to next step.
  7. Check for high resistance in wiring related to ECT sensor. Check for poor connections at ECT sensor and PCM. Repair as necessary. After repairs, go to step  10. If connections are okay, go to step  11.
  8. Check thermostat for proper operation. If thermostat is operating properly, go to step  7. If thermostat is not operating properly, go to next step.
  9. Repair cooling system. After repairs, go to step  12.
  10. Replace loose terminals or faulty wiring. After repairs, go to step  12.
  11. Replace ECT sensor. After replacing sensor, go to next step.
  12. Allow engine to cool completely. Clear DTCs. Start and operate engine at idle. Using scan tool, monitor ENG COOL TEMP display. If ECT reading increases to greater than 68°F (20°C) within 2 minutes, system is okay. If ECT reading does not increase to greater than 68°F (20°C) within 2 minutes, go to step  2.
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