CCU 523908.02 – Rear PTO External Switch Conflict

CCU 523908.02 (CCU )

Code: 523908.02



This fault code is generated when the CCU detects simultaneous ON and OFF signals from the rear PTO external switch. Such conflicting signals indicate a malfunction in the switch or the associated circuitry, leading to unreliable PTO operations.


The control unit degrades the functionality of the rear PTO to prevent unsafe or erratic operation due to the conflicting signals.


  • Inspect External Switch: Check the rear PTO external switch for proper operation. Ensure it does not send conflicting signals when engaged.
  • Check Wiring and Connections: Inspect the wiring and connections of the external switch for any signs of damage, wear, or short circuits. Repair or replace as needed.
  • Test Signal Integrity: Use diagnostic tools to test the integrity of the signals from the switch to the control unit, ensuring there are no simultaneous conflicting signals.
  • Replace Faulty Switch: If the external switch is found to be faulty, replace it to ensure it sends accurate signals.
  • System Reset and Testing: After addressing the issue, reset the control unit and test the rear PTO system to confirm that it operates correctly without conflicts.


Ensuring the reliability and accuracy of the rear PTO external switch is essential for safe and effective PTO operation. Regular inspections and timely replacements of faulty components can help maintain optimal performance.

Control Units: John Deere

John Deere Parts
John Deere Logo