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Home >> Chevrolet >> 2002 >> Impala 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 Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Is the cooling system low on coolant? If yes, repair coolant leak and retest. If no, go to next step.
  3. Turn off the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor. Turn on the ignition, with the engine off. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to step  7. If no, go to next step.
  4. Turn off the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and a known-good ground. Turn on the ignition, with the engine off. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step  6.
  5. Repair the ECT sensor reference low circuit for a high resistance or an open. After repairs, go to step  10.
  6. Repair the ECT sensor signal circuit for a high resistance or an open. 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 50-194°F (10-90°C). See appropriate SENSOR OPERATING RANGE CHARTS article. Does resistance and temperature closely match range table? If yes, go to next step. If no, 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 Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step  2.
  11. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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