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Home >> Buick >> 2001 >> Regal LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0125: ECT Excessive Time To Enter Closed Loop Fuel Control >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. If cooling system is low on coolant, repair coolant leak and retest. If cooling system is not low on coolant, go to next step.
  3. Turn ignition off. Disconnect ECT sensor. See Figure or Figure . Connect a fused jumper wire (3-amp) between ECT sensor connector terminals. Turn ignition on, engine off. Using scan tool, observe ECT sensor temperature. If scan tool indicates ECT sensor temperature is more than 280°F (138°C), go to step  7. If scan tool does not indicate ECT sensor temperature is more than 280°F (138°C), go to next step.
  4. Turn ignition off. Disconnect ECT sensor. Connect a fused jumper wire (3-amp) between ECT sensor connector terminal "B" (Yellow wire) and ground. Turn ignition on, engine off. Using scan tool, observe ECT sensor temperature. If scan tool indicates ECT sensor temperature is more than 280°F (138°C), go to next step. If scan tool does not indicate ECT sensor temperature is more than 280°F (138°C), go to step  6.
  5. Repair high resistance or open in Black wire between ECT sensor and PCM. After repairs, go to step  10.
  6. Repair high resistance or open in Yellow wire between ECT sensor and PCM. After repairs, go to step  10.
  7. Remove ECT sensor. Suspend ECT sensor and a thermometer in a pan of water. Place pan on a burner or hot plate. Check resistance of ECT sensor through specified range of temperatures. See appropriate SENSOR OPERATING RANGE CHARTS article. If resistance and temperature closely match range table, go to next step. If resistance and temperature do not closely match range charts, go to step  9.
  8. Reinstall ECT sensor. Diagnose and repair thermostat. After repairs, go to step  10.
  9. Replace ECT sensor. After repairs, go to next step.
  10. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria. If DTC runs and passes, go to next step. If DTC does not run and pass, go to step  2.
  11. Using scan tool, observe stored information. If scan tool displays any DTCs that have not been diagnosed, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs, system is okay.
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