BCU 523806.09 – Y75 Solenoid for PTO Speed 3, Incorrect CAN BUS Message from BCU (Power Module PC5). John Deere System Advisory.

BCU 523806.09 (BCU )

Code: 523806.09



Error code BCU 523806.09 is triggered when there is a communication failure between the Power Module PC5 and the Basic Control Unit (BCU) specifically related to the Y75 solenoid for PTO Speed 3. This diagnostic trouble code indicates issues in the CAN (Controller Area Network) bus messages, where transmission from the BCU to the power module PC5 is intermittent or completely absent. This problem could be due to loose wiring, damaged connectors, or disruptions in the CAN bus network.


The miscommunication can lead to improper functioning of the PTO Speed 3 solenoid, which may result in unexpected behavior or failure to operate. This impacts the tractor’s ability to utilize the PTO effectively, potentially affecting operations that rely on this power output.


  • Inspect and Secure CAN Bus Connections: Check all connections within the CAN bus system, particularly those between the BCU and Power Module PC5. Look for loose, corroded, or damaged connectors that might affect signal integrity.
  • Test CAN Bus Signal: Use diagnostic tools designed for CAN bus testing to check the signal quality and continuity. Identify and resolve any breaks or interference in the signal path.
  • Replace or Repair Damaged Wiring: If any wiring is found to be faulty or damaged, replace or repair it to ensure reliable data transmission within the CAN bus system.
  • Reset and Reconfigure Systems: After addressing the physical connections and wiring, reset the BCU and Power Module PC5 to clear any fault codes and reinitialize the system settings.
  • Monitor Communication System: After repairs, monitor the communication between the BCU and Power Module PC5 to ensure that messages are being transmitted and received without interruption.
  • Test PTO System Operation: Perform functional tests on the PTO Speed 3 to ensure it operates as expected under normal conditions. Verify that the solenoid responds appropriately to control inputs.
  • Routine System Checks: Regularly schedule inspections and maintenance for the electrical and communication systems of the machinery. Keeping these systems in good working order is essential for the overall reliability and performance of the equipment.
  • Documentation and Training: Document the issue and the steps taken to resolve it, and ensure that personnel are trained on the importance of maintaining the CAN bus system and spotting signs of potential problems.


Effective communication through the CAN bus system is crucial for modern agricultural equipment, where many operational functions are managed electronically. Ensuring that this communication network is functioning correctly is essential for the safe and efficient operation of the equipment. Regular maintenance and prompt attention to communication errors help prevent operational delays and maintain the machinery’s reliability and productivity.