Diagnostic Aids

If the temperature light or gauge indicated overheating, but no boil over is detected, the gauge or light should be checked. The gauge accuracy can also be checked using a scan tool to compare the coolant temperature reading with the gauge reading.

If the engine is actually overheating, and the gauge indicates overheating, but the cooling fan is not operating, the Engine Coolant Temperature (ETC) sensor may have shifted out of calibration and should be replaced.

If the engine is overheating and the cooling fan is operating, the cooling system should be checked.