manurefactured controll air meter p1299 on 2000 Lincoln LS

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my computer in my car said I was loosing engine power I stopped at advanced auto and had the car scanned and this is what came up what does this mean?nobody else seems to know.
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Here is the info from Chrysler. This is an odd code, did you have any issues with the engine overheating?

Trouble Code: P1299 3.9L V8
Cylinder Head Over-Temperature Protection Active
Trouble Code Conditions:
Engine started, and after a period of time with the engine running, the PCM detected the engine was in an overheated condition.
Note: The PCM enables the Fail-Safe Cooling whenever this code is set to cool the engine.
Possible Causes:
* Cooling system has a problem
* Engine coolant level is too low
* A Base Engine problem may be present
1. Check coolant level.
* If the coolant level is correct, perform a Cooling System diagnosis.
* If the coolant level is not correct, check cooling system for loss of engine coolant.
A shop would check the coolant level and condition, check for proper thermostat and cooling fan operation and check all the hoses, water pump and radiator condition. Perform a pressure check and look for any leaks.
what would a cooling system diagnosis consist of?