Circuit/System Verification

Engine running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P00B6, P0116, P0117 or P0118 should not be set.
- If DTC P00B3, P00B4, P00B6, P0116, P0117 or P0118 is set.
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
- If DTC P00B3, P00B4, P00B6, P0116, P0117 or P0118 is not set.
Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks.
- If the coolant in the radiator surge tank is not at the correct level or there are engine coolant leaks
  Refer to Cooling System Draining and Filling (GE-47716 Fill) , Cooling System Draining and Filling (Static Fill) and Loss of Coolant .
- If the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks
Verify the engine cooling fan operates. Using the scan tool, select Control Functions, Cooling Fan, Cooling Fan Relays 1, 2 and 3. Command the Cooling Fan ON and OFF.
- If the cooling fan does not turn ON and OFF
  Refer to Cooling Fan Inoperative (LUW, LUV or LWE) .
- If the cooling fan turns ON and OFF
Engine idling for 15 minutes with the A/C OFF.
Command the Engine Coolant Thermostat Heater to 100% with a scan tool. Increase the engine speed to 3, 000 RPM. Observe the scan tool ECT sensor parameter. The temperature should decrease to less than 85°C (185°F).
NOTE: Depending on ambient temperature, it may take up to 4 minutes for the temperature to decrease less than the specified value.
- If ECT is warmer than 85°C (185°F)
  Refer to Circuit/System Testing .
- If ECT is colder than 85°C (185°F)
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set.
- If the DTC sets
  Refer to Circuit/System Testing .
- If the DTC does not set
All OK.