Circuit/System Verification
- Ignition OFF, inspect the cooling system surge tank for the proper coolant level. Refer to Cooling System Leak Testing and Cooling System Draining and Filling (LS4 GE47716 Fill) or Cooling System Draining and Filling (LS4 Static Fill) .
- Ignition OFF for 8 hours or greater.
- Ignition ON, observe the scan tool IAT and ECT sensor parameters. The ECT, IAT, and ambient temperatures should be within 6°C (11°F) of each other.
- Use the scan tool to verify the proper operation of the engine cooling system fans.
- Verify the proper range and the operation of the thermostat. Refer to Thermostat Diagnosis (3.6L (LY7)) .
- 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.
CAUTION:
Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap. Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use any time. Flammable antifreeze could cause a serious fire.
IMPORTANT:
A critical analysis of the operation of the thermostat is necessary to properly diagnose these DTCs.