BCU 523692.09 – Upper Worklights on Cab Frame, Incorrect CAN Bus Message from BCU (Power Module PC0). John Deere System Advisory.

BCU 523692.09 (BCU )

Code: 523692.09



Error code BCU 523692.09 is triggered when there is a communication issue between the Power Module PC0 and the Basic Control Unit (BCU) in a John Deere vehicle, specifically affecting the upper worklights on the cab frame. This diagnostic trouble code indicates that the reception of one or more CAN bus messages from the BCU to power module PC0 is intermittent or entirely absent, possibly due to loose wiring or a fault within the communication system.


This communication failure may lead to improper functioning of the upper worklights, such as failure to turn on or off as commanded, which can affect visibility and operational safety.


  • Inspect CAN Bus Connections: Examine the connections between the BCU and Power Module PC0, particularly focusing on the connectors and wiring associated with the upper worklights. Ensure all connections are secure and free from corrosion or damage.
  • Check for Loose Wiring: Look for any loose wires that might be causing intermittent CAN bus communication. Secure any loose connections and replace damaged wiring.
  • Use Diagnostic Tools: Utilize CAN bus diagnostic tools to monitor the communication between the BCU and Power Module PC0. Check for errors or interruptions in data transmission that could indicate where the communication breakdown is occurring.
  • Resolve Wiring or Hardware Issues: Repair or replace any faulty wiring or hardware that is contributing to the communication problems. Ensure that all components are properly installed and functioning.
  • Reset the Power Module and BCU: After addressing any physical connection issues or faults, reset both the power module and the BCU to clear the error codes and reinitialize the communication protocols.
  • Test the System: Ensure that the upper worklights operate correctly and respond to commands from the BCU without delay or error. Continue to monitor the CAN bus system to ensure communication is consistent and reliable.
  • Continuous System Monitoring: Implement regular checks of the CAN bus system to ensure ongoing reliability of communication, particularly for systems critical to safety and operation such as lighting.


Proper configuration and maintenance 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.