What does it mean?
This diagnostic trouble code (DTC) is a generic powertrain code, meaning it applies to vehicles equipped with OBD-II. Although generic, specific repair steps may vary by make/model.
Having this code stored means your vehicle is equipped with an engine overheating warning light that will illuminate in case of overheating. Most modern vehicles also have a temperature gauge, but some do not.
An overheating condition is typically above 240-250°F (will vary by manufacturer) in the cooling system. The overheating light is designed to come on before the engine sustains damage, but shutting off the engine as soon as possible should be your first priority.
Symptoms
Symptoms of a DTC P0217 may include:
MIL (Malfunction Indicator Light) illumination
Loss of power
Coolant expelled from the reservoir or radiator
Low coolant level
Acrid smell of coolant due to a leak
Inoperative air conditioning (in case of overheating, the PCM (Powertrain Control Module) on some vehicles shuts off the A/C system to reduce engine load).
Causes
Potential causes of a P0217 code include:
Low coolant due to a leak in the 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 the cooling system
Towing an overloaded trailer
Faulty water pump (broken/damaged impeller)
Possible Solutions
Start by checking the coolant level ON A COLD ENGINE. It is never a good idea to check coolant on a hot or overheated engine. Additionally, adding cold water to an empty, overheated cooling system causes thermal shock and is not advisable.
If you find your cooling system is low on coolant and you have a stored P0217, inspect the system for leaks and repair as needed. Then replace the thermostat (see note below) and after refilling the cooling system, restart the engine and verify it does not overheat. Be aware that an overheating engine may expel coolant from the radiator cap to protect the cooling system from overpressure. If you cannot locate a leak, this may be the reason.
Follow the steps below to check cooling system performance. If the coolant level is normal, check the radiator and A/C condenser for any type of restriction that could impede airflow. This step may require removing the radiator and visually inspecting it outside the vehicle. Check between the radiator and condenser for any restrictions or debris. Ensure all plastic panels that direct airflow into the radiator are in place. If you have access to a scan tool, check the operation of the cooling fans or any abnormal noise indicating bearing failure. Look into the radiator tank (if possible) and observe its condition. Is there significant buildup that could restrict coolant flow? If so, replace the radiator.
If you notice no apparent issues and the vehicle continues to overheat, feel the upper radiator hose. Is it hot, indicating coolant is flowing freely? If not, the water pump impeller may be damaged or broken, causing a no-flow condition. If the water pump appears to be functioning correctly, the thermostat may be faulty. Replace it and recheck. If, after the above checks, you still have overheating issues and coolant being expelled from the system, combustion gases may be leaking into the cooling system. This would require a combustion gas leak test on the cooling system. If you have a P0217 but the vehicle is not overheating, there may be a faulty coolant temperature sensor.
Note: An overheated engine can actually damage the thermostat. Therefore, it is always best to replace the thermostat after an overheating event. If you do not, you may successfully repair the original cause of the overheating but still have an overheating condition due to the damaged thermostat.