BCU 001894.31 – Rear PTO Switch On at Engine Start. John Deere System Advisory.

BCU 001894.31 (BCU 1894.31)

Code: 001894.31

Shortcode: 1894.31


Error code BCU 001894.31 is an informational alert generated when the rear Power Take-Off (PTO) switch is in the “on” position at the time of starting the engine or turning on the ignition of a John Deere vehicle. This alert is designed to inform the operator that starting the engine with the PTO engaged can lead to safety issues or mechanical stress. If the diagnostic trouble code appears even though the rear PTO was confirmed to be off while starting the engine, it indicates a potential malfunction in the rear PTO switch, suggesting an operational check is necessary.


The BCU may display this code to prompt the operator to check the PTO settings and ensure that the PTO is not unintentionally engaged during engine start, which could prevent accidental activation and potential damage.


  • Verify Rear PTO Switch Position: Check the position of the rear PTO switch before starting the engine to ensure it is in the “off” position.
  • Perform Rear PTO Switch Operational Check: If the code appears erroneously, perform an operational check of the rear PTO switch as detailed in Section 245, Group BCU of the service manual. This will help identify any issues with the switch’s functionality.
  • Inspect Wiring and Connections: Examine the wiring and connections of the rear PTO switch for any signs of damage or corrosion that could affect its operation. Repair or replace faulty components as necessary.
  • Test Switch Functionality: Use diagnostic tools to confirm that the rear PTO switch operates correctly and consistently registers the “on” and “off” positions accurately.
  • Reset the BCU and Clear Diagnostic Codes: Once any necessary repairs or adjustments have been made, reset the BCU to clear the error code and verify that the system recognizes the correct state of the rear PTO switch.
  • Document the Maintenance: Keep a record of the checks and any repairs done to address this diagnostic code for future reference and to aid in ongoing maintenance strategies.


Ensuring that the rear PTO switch operates correctly is crucial for safe tractor operation. Regular maintenance checks and immediate attention to any alerts related to PTO operation can help prevent accidents and equipment damage, promoting a safe working environment. This proactive approach helps maintain the effectiveness and reliability of your John Deere equipment.