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Home >> Chevrolet >> 2009 >> HHR SS, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 2.0L - DTC P0010 To DTC P0238 >> 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 (Static Fill-LE5, L61) or Cooling System Draining and Filling (Static Fill-LNF) or Cooling System Draining and Filling (GE 47716 Fill) .
  3. If the ignition has been OFF for 8 hours or greater, the IAT sensor, the IAT sensor 2 and the ECT sensor should be within 9°C (16°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2, and the ECT Sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the ECT sensor is skewed colder.
  4. Engine running, observe the ECT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.
  5. Use the scan tool to verify the proper operation of the engine cooling system fans.
    6. IMPORTANT: A critical analysis of the operation of the thermostat is necessary to properly diagnose this DTC.
  6. Verify the proper heat range, and the operation of the thermostat. Refer to Thermostat Diagnosis .
  7. 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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