CAB 523839.02 – Secondary Brake Switch Conflict

CAB 523839.02 (CAB )

Code: 523839.02



The fault code CAB 523839.02 is identified when the CAB control unit detects an anomaly in the secondary hand brake switch, specifically that the signal appears to be both open and closed at the same time. This kind of signal conflict could be due to a malfunctioning switch, faulty wiring, or an electronic error in the control system. Note that this pertains to the secondary brake system used in European versions of the equipment, which acts as an auxiliary brake, not a parking brake.


Despite the conflicting signals from the secondary brake switch, the control unit takes no action to change or restrict the vehicle’s operation, relying on other systems to maintain braking functionality.


  • Inspect the Brake Switch: Thoroughly examine the secondary brake switch for physical defects or damage that might cause irregular signals. Check for any signs of wear or mechanical failure.
  • Check Electrical Continuity: Use electrical testing tools to measure the continuity and isolation within the switch circuit. This will help identify if there is a short circuit or other electrical issues contributing to the signal conflict.
  • Verify Wiring Integrity: Inspect all wiring connected to the secondary brake switch. Ensure there are no frayed wires, loose connections, or corrosion that could disrupt signal integrity.
  • Replace Faulty Components: If testing confirms a fault in the switch or associated wiring, replace these components to ensure reliable operation of the secondary brake system.
  • Test System Post-Repair: After addressing potential faults, perform a comprehensive system test to verify that the switch operates correctly and consistently without signal conflicts.


Maintaining the integrity of all brake system components is crucial for safety. Regularly scheduled inspections and prompt resolution of any identified issues help ensure that auxiliary systems like the secondary brake operate effectively and do not compromise the overall safety of the vehicle.

Control Units: John Deere

John Deere Parts
John Deere Logo