CCU 524223.03 – Differential Lock Switch Circuit Voltage High

CCU 524223.03 (CCU )

Code: 524223.03



This fault code is activated when the Chassis Control Unit (CCU) detects that the differential lock switch has been closed for more than 15 seconds after power-up. This condition may be caused by an obstruction, such as a foot or floor mat, inadvertently pressing the switch.


The differential lock cannot be engaged while this fault is active, to prevent potential damage or unsafe operation.


  • Check Differential Lock Switch: Ensure that nothing is resting on or obstructing the differential lock switch, such as a foot or floor mat.
  • Inspect Switch and Wiring: Examine the differential lock switch and its wiring for any signs of damage, wear, or electrical faults. Repair or replace as necessary.
  • Reset System: After resolving any obstructions or electrical issues, reset the CCU and verify that the differential lock switch operates correctly.
  • Test Differential Lock Function: Engage and disengage the differential lock to ensure it functions properly without triggering the fault code.


Regular inspection and maintenance of switches and their surroundings can help prevent such issues. Ensuring the differential lock switch is free from obstructions and in good working condition is crucial for safe and effective operation.

Control Units: John Deere

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