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Home >> Isuzu >> 1996 >> Hombre S >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Testing >> DTC P0125 - ECT Excessive Time To Reach Closed Loop >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Allow engine to cool to ambient temperature. Turn ignition on, with engine off. Using scan tool, compare ECT sensor temperature reading to IAT sensor temperature sensor reading. If readings are close to each other, go to step 4). If readings are not close to each other, go to next step.
  3. Disconnect ECT sensor connector. Using DVOM, check ECT sensor resistance. See ECT TEMPERATURE-TO-RESISTANCE VALUES table. If ECT resistance value is close as indicated, go to step 4). If ECT resistance value is not as specified, go to step 9). See ECT TEMPERATURE-TO-RESISTANCE VALUES.
  4. Turn ignition on, with engine off. Disconnect ECT sensor connector. If scan tool indicates ECT sensor temperature is less than -22°F (-30°C), go to next step. If scan tool indicates ECT sensor temperature is -22°F (-30°C) or greater, go to step 8).
  5. Connect a jumper wire between signal circuit and sensor ground circuit terminals at ECT sensor harness connector. If scan tool value is greater than 266°F (130°C), go to next step. If scan tool value is 266°F (130°C) or less, go to step 7).
  6. Check cooling system for proper operation. Repair as necessary. After repair is completed, go to step 10). If cooling system is functioning properly, see DIAGNOSTIC AIDS.
  7. Disconnect and inspect ECT sensor and PCM connectors. Repair connectors as necessary. After repair is completed, go to step 10). If connectors are okay, go to next step.
  8. Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to next step.
  9. Replace ECT sensor. After repair is completed, go to step 10).
  10. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0125. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2).
  11. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.
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