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DTC P0125: Closed Loop Temperature Not Reached

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.
NOTE: Closed loop operation is monitored after engine has been running for 10 minutes. DTC may be stored in Powertrain Control Module (PCM) if engine temperature does not increase more than 60°F (15°C) in 10 minutes after engine is started. Possible causes are: defective thermostat, defective Engine Coolant Temperature (ECT) sensor or low coolant level.
  1. Ensure coolant is in good condition and at proper level. Correct coolant level as necessary. Perform TEST VER-2A . If coolant is okay, go to next step.
  2. Start engine and allow to warm to normal operating temperature. Using a thermometer, measure engine coolant temperature. If thermometer indicates normal engine operating temperature, go to next step. If thermometer does not indicate normal engine operating temperature, replace thermostat. Perform TEST VER-2A .
  3. Shut engine off. Disconnect ECT sensor connector. See Figure. Measure resistance between ECT sensor component terminals. Ensure engine coolant temperature is more than 80°F (26.7°C). If resistance is less than 11 k/ohms, test is complete. Problem is intermittent. If resistance is 11 k/ohms or more, replace ECT sensor. Perform TEST VER-5A .
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