BCU 523839.31 – Information for Operator: Handbrake Activated While Wheel Speed is Recognized. John Deere Advisory.

BCU 523839.31 (BCU )

Code: 523839.31



Diagnostic trouble code BCU 523839.31 is generated as an informational alert when the Basic Control Unit (BCU) detects wheel speed despite the handbrake being engaged. This condition indicates that the vehicle is in motion or experiencing wheel movement while the handbrake is supposedly active, which could suggest a malfunction of the handbrake system or incorrect status reporting. This code serves as a real-time warning to the operator and is not stored in the control unit’s error memory.


The system provides an immediate alert to the operator to address the potentially unsafe condition. There is no automatic corrective action taken by the system; it relies on the operator to manually check and resolve the issue.


  • Acknowledge the Alert: Operators should immediately check the status of the handbrake and the actual motion of the vehicle upon receiving this alert.
  • Inspect Handbrake Functionality: Ensure that the handbrake is fully engaged when intended and that it effectively stops the vehicle from moving. If the vehicle moves with the handbrake engaged, a mechanical inspection and possible repair are necessary.
  • Check for Sensor Issues: Investigate if the wheel speed sensors are functioning correctly and not falsely reporting wheel movement. Sensor malfunctions could trigger this alert erroneously.
  • Routine Maintenance Checks: Regular maintenance checks should include an assessment of the handbrake system and wheel speed sensors to ensure correct operation and calibration.
  • Operator Training: Reinforce training for operators on the importance of ensuring the handbrake is properly engaged before exiting the vehicle and checking for any signs of movement if the handbrake is supposed to be active.


Prompt attention to such alerts is crucial for safety and operational efficiency. Operators should be trained to respond immediately to any warnings indicating potential safety hazards, such as movement with the handbrake engaged. Regular checks and maintenance can prevent these issues and ensure the handbrake system functions as expected, providing a safe working environment.

Control Units: John Deere

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