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Home >> Isuzu >> 1996 >> Rodeo LS, 2.6 E >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.6L 4-CYL >> Circuit Testing >> DTC P0125 - ECT Excessive Time To Reach Closed Loop >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. If any ECT DTCs are set, diagnose affected DTC before proceeding. If no ECT DTCs are set, go to next step.
  3. Check coolant level. If coolant level is low, go to step 9) If coolant level is okay, go to next step.
  4. Allow engine to cool completely. Turn engine on and allow it to idle. Using scan tool, monitor ENG COOL TEMP. If temperature increases to 70°F (21°C) within 2 minutes, see DIAGNOSTIC AIDS. If specified temperature is not reached within 2 minutes, go to next step.
  5. Check thermostat operation. If thermostat is operating correctly, go to next step. If thermostat is not operating correctly, go to step 9).
  6. Compare actual coolant temperature with scan tool ECT value. If temperatures are close in value, go to step 9). If temperatures are not close in value, go to next step.
  7. Turn ignition off. Disconnect PCM. Using a DVOM, measure ECT resistance at PCM connector and compare DVOM readings with ECT SENSOR TEMPERATURE VS. RESISTANCE VALUES table. If chart values equal readings, go to step 12). If chart values do not equal readings, go to next step.
  8. Check for high resistance in wiring related to ECT sensor and for poor connections at ECT sensor and PCM. If a problem is found, go to step 10). If no problem is found, go to step 11).
  9. Repair cooling system as necessary and go to step 13).
  10. Repair terminal as necessary and go to step 13).
  11. Replace ECT sensor and go to step 13) .
  12. Replace PCM and go to next step.
  13. Allow engine to cool completely. Using scan tool, clear DTCs. Turn engine on and allow it to idle. Using scan tool, monitor ENG COOL TEMP. If temperature increases to 71.6°F (22°C) within 2 minutes, repair is complete. If specified temperature is not reached within 2 minutes, return to step 2).
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