Technical Definition:

Engine Coolant Over Temperature Condition

Technical Description:

Possible Causes:

• Low coolant due to leak in cooling system
• Restriction/debris in the A/C condenser or radiator
• Restriction/debris in the cooling system
• Thermostat stuck closed or faulty
• Inoperative cooling fan(s)
• Cylinder head gasket leaking combustion into cooling system
• Overloaded trailer towing
• Faulty water pump (impeller broken/damaged)

Possible Symptoms:

• MIL (malfunction indicator lamp) illumination
• Loss of power
• Coolant expelled from reservoir or radiator
• Low coolant
• Acrid smell of coolant due to leak
• Air conditioner inoperative (In the event of an overheat condition, the PCM (powertrain control module) on some vehicles shuts down the A/C system to reduce load on the engine).

Engine Overheat Condition

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty cooling fan
– Faulty Thermostat
– Faulty engine temperature sensor
– Cooling fan harness is open or shorted
– Cooling fan poor electrical connection
– Engine temperature sensor harness is open or shorted
– Engine temperature sensor poor electrical connection
– Improper ignition timing
– Blocked radiator

Specific Makes: