PTH 521991.00 – Controller Temperature Data Valid but Above Normal Operational Range – Most Severe Level

PTH 521991.00 (PTH )

Code: 521991.00



This fault code indicates that the PTH (Power Train Hydrostatic) controller temperature is severely high, exceeding the normal operational range. This can be due to overheating, insufficient cooling, or a failing controller.


When this error is detected, the equipment may shut down or enter a safe mode to prevent damage due to the high temperature of the controller.


Replace Controller:

  • The primary recommendation is to replace the PTH controller to ensure normal operation.

Check Cooling System:

  • Ensure that the cooling system is functioning properly.
  • Check for any obstructions or blockages in the cooling vents and fans.
  • Clean or replace air filters if necessary.

Verify Environmental Conditions:

  • Ensure the equipment is operating in an environment within the specified temperature range.
  • Avoid exposure to excessive heat or direct sunlight.

Monitor System Performance:

  • After replacing the controller, monitor the system to ensure normal operation and that the fault does not reappear.

Consult Technical Support:

  • If the issue persists, contact technical support for further diagnostics and assistance.


Regular maintenance and inspection of the cooling system can prevent such issues. Ensure proper ventilation around the equipment and maintain a clean environment to avoid overheating.

Control Units: John Deere

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