BCU 523746.31 – Control Unit Internal Fault Detected in Tractor BUS System Activation. John Deere System Advisory.

BCU 523746.31 (BCU )

Code: 523746.31



Diagnostic trouble code BCU 523746.31 is activated when the Body Control Unit (BCU) detects no current flow at the signal output designated for activating the tractor BUS system. This condition suggests that the circuit is either shorted to a positive supply lead or there is an internal interruption within the control unit itself. Such faults can compromise the communication and operational functionality of the tractor’s BUS system, potentially affecting multiple systems reliant on this network.


The BCU may initiate a protective shutdown of the BUS system or related components to prevent further damage or erratic behavior of the tractor systems.


  • Inspect and Test Circuit Connections: Thoroughly examine the circuit connections for any signs of shorting to the positive supply. Use multimeters or other diagnostic tools to test continuity and identify potential shorts or breaks in the circuit.
  • Check for Internal Faults in the BCU: Since the issue may involve internal faults within the BCU, consider testing the unit with specialized diagnostic equipment to confirm its integrity. Look for signs of physical damage or component failure.
  • Replace or Repair Damaged Components: If an internal fault or damage within the BCU is identified, it may be necessary to replace or repair the unit. Ensure that any replacement parts are compatible and properly configured.
  • Reset the System: After any necessary repairs or replacements, reset the BCU and any related systems to clear fault codes and re-establish proper operational settings.
  • Verify System Functionality: Conduct comprehensive tests to ensure that the tractor BUS system and all related components are functioning correctly following the intervention.


Regular diagnostics and maintenance of the control unit and its associated circuits are crucial for ensuring the reliability and efficiency of tractor operations. Addressing internal faults promptly and effectively helps minimize downtime and maintains the performance and safety standards required for agricultural machinery.