BCU 523811.09 – Incorrect CAN BUS Message for Y73 Solenoid, PTO Speed 1. John Deere System Advisory.

BCU 523811.09 (BCU )

Code: 523811.09



Diagnostic trouble code BCU 523811.09 is activated when there is a communication issue between the power module PC5 and the Body Control Unit (BCU). This fault is identified when the reception of one, several, or all CAN messages transmitted by the BCU to power module PC5 is intermittent or nonexistent, potentially due to loose wiring or other connectivity problems. This issue affects the proper operation of the Y73 solenoid for PTO (Power Take-Off) Speed 1, which relies on these messages for correct functioning.


The system may temporarily disable the Y73 solenoid or issue a fault response to prevent incorrect operation based on the flawed data transmission. This may include alerts or warnings to the operator indicating the need for system inspection and correction.


  • Inspect CAN Bus Connections: Thoroughly check all related CAN bus connections between the BCU and power module PC5, ensuring they are secure and free from corrosion or damage.
  • Test Wire Continuity and Security: Use diagnostic tools to test the continuity of the wires involved in the CAN bus system. Focus on identifying any loose or intermittent connections that could be disrupting communication.
  • Resolve Connectivity Issues: Tighten or replace any loose or damaged connectors or wiring found during the inspection.
  • Check for CAN Bus Interference: Ensure that there is no electromagnetic interference affecting CAN bus communication. Keep wiring away from high voltage lines or equipment that may emit strong electromagnetic fields.
  • Reset and Reconfigure Systems: After ensuring all physical connections are intact and secure, reset the CAN bus system and reconfigure settings if necessary to ensure proper communication protocols are followed.
  • Monitor System Performance: Continuously monitor the system to ensure that communication has been fully restored and that no further message errors are occurring.


Maintaining reliable communication across the CAN bus is crucial for the efficient operation of all interconnected vehicle systems. Regular diagnostics and proactive maintenance can help avoid communication failures and ensure that the equipment operates smoothly and effectively. Ensuring clear and correct communication pathways within vehicle control systems is essential for operational reliability and accuracy.