BCU 523904.31 – Information for Operator: Operator Presence Switch Not Activated While Front PTO is Engaged. John Deere Advisory.

BCU 523904.31 (BCU )

Code: 523904.31



Diagnostic trouble code BCU 523904.31 is issued as an informational alert when the front PTO (Power Take-Off) is engaged without the operator presence switch being activated. This situation generally indicates that the operator has left the seat while the PTO is still operating, which poses a safety risk. The alert is designed to notify the operator of the need to be seated to safely operate the PTO. If the alert occurs while the operator is indeed seated, it suggests a possible malfunction or incorrect reading from the operator presence switch.


The system does not store this as a fault but uses it to prompt immediate action or checks by the operator to ensure safety protocols are followed. The PTO system may be designed to automatically disengage or prevent engagement while the operator presence switch is not activated.


  • Check Operator Seat Position: Ensure that you are correctly seated with all safety belts (if present) secured, as this may affect the switch activation.
  • Inspect Operator Presence Switch: Look for any visible issues with the operator presence switch such as loose connections, damage, or wear that could affect its function.
  • Perform Operational Check: Refer to “S40 Operator Presence Switch, Operational Check” in Section 245, Group BCU for detailed instructions on testing the functionality of the switch to ensure it operates as intended.
  • Adjust or Replace the Switch: If the switch fails the operational check, adjust its positioning or replace it if necessary to ensure it correctly detects the presence of an operator.
  • Consult Technical Support: If issues persist after these checks, consult with John Deere technical support for further diagnostics or advice.


Operator presence systems are critical safety features on modern agricultural machinery. Ensuring that these systems are functioning correctly is vital for the safe operation of the equipment. Regular maintenance checks and adherence to safety guidelines help prevent accidents and ensure that the equipment operates smoothly and efficiently.

Control Units: John Deere

John Deere Parts
John Deere Logo