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Home >> Saturn >> 2009 >> Sky Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 2.4L - DTC P0010 To DTC P0366 >> DTC P0128 >> Circuit/System Verification
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Circuit/System Verification

  1. Turn OFF the ignition.
  2. Inspect the cooling system surge tank for the proper engine coolant level. Refer to Cooling System Leak Testing and Cooling System Draining and Filling (GE-47716) or Cooling System Draining and Filling (2.4L LE5) .
  3. If the ignition has been OFF for 8 hours or greater, the ECT and the IAT should be within 15°C (27°F) of each other and also the ambient temperature. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the IAT and the ECT sensor parameters.
  4. Use the scan tool to verify the proper operation of the engine cooling system fans.
    5. IMPORTANT: A critical analysis of the operation of the thermostat is necessary to properly diagnose this DTC.
  5. Verify the proper heat range, and the operation of the thermostat. Refer to Thermostat Diagnosis .
  6. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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