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Home >> Isuzu >> 2003 >> Rodeo LS, 2.2 D >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Tests >> DTC P0125: Insufficient Temperature For Closed Loop Fuel Control >> Diagnostic Procedures

Diagnostic Procedures

CAUTION: Use extreme caution when opening cooling system to measure coolant temperature.
  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. If any related ECT DTCs are set, diagnose affected DTC before proceeding. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no related ECT DTCs are set, go to next step.
  3. Allow engine to cool. Check coolant level. If coolant level is okay, go to next step. If coolant level is low, go to step  9 .
  4. Start engine and allow it to idle. Using scan tool, monitor ENG COOL TEMP parameter. If temperature increases to 70°F (21°C) within 2 minutes, check for intermittent problem. 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. Using thermometer, measure coolant temperature. Compare actual coolant temperature with scan tool ECT sensor parameter. 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 harness connectors C-2 (White) and C-3 (Tan). Using DVOM, measure resistance between PCM harness connector C-2 terminal D8 (Green wire) and PCM harness connector C-3 terminal E9 (Blue/Red wire). See Figure . Compare DVOM readings with ENGINE COOLANT TEMPERATURE SENSOR SPECIFICATIONS  table in TEST DESCRIPTION. If measured resistance is as specified, go to step  12 . If measured resistance is not as specified, go to next step.
  8. Check for open, short to ground or short to voltage in Blue/Red and Green wires between ECT sensor and PCM. See WIRING DIAGRAMS  . If a problem was found, go to step  10 . If no problem was found, go to step  11 .
  9. Repair cooling system as necessary. After repairs are complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  10. Repair wiring or terminals as necessary. After repairs are complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  11. Replace ECT sensor. After repairs are complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
  12. Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE REPLACEMENT  under POWERTRAIN CONTROL MODULE. After repairs are complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
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