BCU 523920.19 – Outer Worklights on Front of Roof, Incorrect CAN BUS Message. John Deere System Advisory.

BCU 523920.19 (BCU )

Code: 523920.19



Diagnostic trouble code BCU 523920.19 is triggered when there is a communication error involving the outer worklights on the front of the roof (E18/2), specifically the output being energized by more than one control unit. This error typically results from a misconfiguration in the CAN (Controller Area Network) bus system, leading to multiple signals being sent to activate the same function, which can cause conflicting commands and erratic operation of the worklights.


To prevent potential malfunctions or safety issues, the system might temporarily disable the affected worklights or issue a warning alert on the operator’s panel, prompting an investigation into the source of the communication error.


  • Diagnose CAN Bus Communication: Utilize diagnostic tools to analyze the communication paths within the CAN bus system. Identify and resolve 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 E18/2 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 E18/2 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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