CCU 523839.02 – Secondary Brake Switch Conflict

CCU 523839.02 (CCU )

Code: 523839.02



This fault code is generated when there is a conflict between the states indicated by the secondary brake switches. Specifically, the secondary brake is either disengaged while the switch indicates it is on, or engaged while the switch indicates it is off. This conflict arises when the normally open (NO) and normally closed (NC) switches both indicate conflicting states continuously for more than 0.5 seconds.


The control unit degrades the functionality of the braking system to ensure safety and prevent potential damage due to the conflicting brake states.


  • Inspect Brake Switches: Check the secondary brake lever’s NO and NC switches for proper operation. Ensure they are not damaged or misaligned.
  • Test Electrical Connections: Verify that all electrical connections to the brake switches are secure and free from corrosion or damage.
  • Adjust or Replace Switches: If the switches are found to be faulty, adjust or replace them to ensure they provide accurate and consistent signals.
  • Verify Brake Operation: Test the brake system to confirm that the switches correctly indicate the brake’s engaged and disengaged states without conflicts.
  • Reset and Monitor: After making necessary adjustments or replacements, reset the system and monitor the brake switches to ensure the conflict does not recur.


Accurate and reliable operation of the brake switches is critical for vehicle safety. Regular inspections and prompt attention to any switch-related issues can help maintain effective braking performance and prevent accidents.

Control Units: John Deere

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