BCU 523921.19 – E11/2 /E31R Worklights on Rear of Roof, Incorrect CAN BUS Message. John Deere System Advisory.

BCU 523921.19 (BCU )

Code: 523921.19



Diagnostic trouble code BCU 523921.19 is triggered when the output for switching the worklights on the rear of the roof (E11/2 or E31R) is erroneously energized by more than one control unit. This issue typically results from a misconfiguration within the CAN (Controller Area Network) bus system, leading to multiple control units attempting to control the same function. This can cause conflicting commands and potentially erratic operation of the worklights.


The system might temporarily disable the affected worklights or issue a warning alert on the operator’s panel to prevent potential malfunctions or safety issues arising from this communication error.


  • Diagnose CAN Bus Communication: Use diagnostic tools to analyze the communication paths within the CAN bus system. Identify any misconfigurations or errors that are causing multiple control units to energize the same output.
  • Reconfigure System Settings: Adjust the settings in the control units to ensure that only the correct unit sends activation signals for the E11/2 or E31R worklights. Remove any duplicate configurations or correct misassigned controls.
  • Inspect and Secure Wiring Connections: Check all related wiring connections to ensure they are correct and secure, as poor connections can sometimes contribute to communication errors.
  • Test System Operation: After making adjustments, thoroughly test the system to ensure that the E11/2 and E31R worklights operate correctly, with signals being correctly issued by the appropriate control unit without any overlaps.
  • Update Software/Firmware: If necessary, update the software or firmware of the involved control units to enhance their communication protocols and prevent future issues.


Maintaining clear and precise communication in vehicle control systems is crucial for operational reliability. Regular system checks and updates of the system configurations and CAN BUS protocols are necessary to prevent communication errors and ensure that each component functions correctly as part of the overall system architecture. Addressing these issues promptly helps maintain the operational efficiency and safety of the equipment.

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