BCU 523691.19 – Lower Worklights on Cab Frame, Incorrect CAN Bus Message (Power Module HF PC6). John Deere System Advisory.

BCU 523691.19 (BCU )

Code: 523691.19



Error code BCU 523691.19 is triggered when the Power Module (High Frequency) PC6 in a John Deere vehicle receives conflicting signals due to the output for the lower worklights on the cab frame (E20/R and E20/L) or the xenon (HID) worklights on the cab frame (E36/R and E36/L) being energized by more than one control unit. This diagnostic trouble code indicates a problem with the CAN bus communication system, where multiple control units are attempting to control the same lighting function, leading to potential operational conflicts or errors in light activation.


The system may exhibit erratic behavior in the operation of the affected worklights, including unexpected switching on/off or failure to respond to control inputs, potentially compromising visibility and safety.


  • Inspect CAN Bus Configuration: Review the configuration of the CAN bus system to identify which control units are sending commands to the worklights. Ensure that only one control unit is designated to control these lights.
  • Check for Programming Errors: Use diagnostic software to check for programming or configuration errors within the control units that might be causing the overlap in commands.
  • Resolve Configuration Conflicts: Adjust the system settings or reprogram the control units as necessary to eliminate any conflicts, ensuring that each output is controlled by only one unit.
  • Reset the Power Module and BCU: After making any necessary adjustments to the configuration or programming, reset both the power module and the BCU to clear the error codes and reinitialize the system.
  • Test System Functionality: Conduct tests to ensure that the lower and xenon (HID) worklights operate correctly, responding to commands as expected without interference from multiple control signals.
  • Monitor System Post-Repair: Continue monitoring the system to ensure that the worklights function consistently and reliably under normal operation conditions. Check that no further CAN bus message errors are reported.


Proper configuration and management of CAN bus communication are crucial for the integrated operation of vehicle systems. Ensuring that communication paths are correctly set up and that control units are not overlapping in their functions is essential for maintaining the reliability and safety of the vehicle’s electrical and lighting systems. Regular checks and updates of the system configurations can prevent potential operational conflicts and ensure smooth operation of all connected devices.