BCU 523756.18 – M08 Stepper Motor for Hitch, Lowering Deadband Too Low During Calibration. John Deere System Advisory.

BCU 523756.18 (BCU )

Code: 523756.18



Error code BCU 523756.18 is activated when the Basic Control Unit (BCU) of a John Deere vehicle detects that the lowering deadband—the minimal play between the adjustment cam of the stepper motor and the lower valve of the hitch valve—is below the specified minimum tolerance during the calibration process. This condition indicates that the components are too tightly configured, which can lead to a lack of cushion or flexibility in the hitch’s movement, increasing the risk of mechanical wear or abrupt hitch movements.


The too low deadband can cause the hitch to respond overly sensitively to lowering commands, potentially leading to jerky or unstable hitch movements. This overly tight configuration can cause rapid wear on mechanical components and affect the longevity and reliability of the hitch system.


  • Inspect and Adjust the Stepper Motor and Hitch Valve Mechanism: Check the physical connections between the stepper motor and the hitch lower valve. Adjust the mechanical linkage or the cam setup to increase the deadband to within the specified tolerances.
  • Re-calibrate the Hitch System: After making the necessary mechanical adjustments, recalibrate the hitch system to ensure that the stepper motor operates within the correct parameters. This will help optimize the responsiveness and precision of hitch adjustments.
  • Reset the BCU: Clear any related diagnostic trouble codes and reset the BCU to ensure it accurately processes inputs from the recalibrated hitch system and operates optimally.
  • Test Hitch Operation: Perform tests to ensure that the hitch raises and lowers smoothly and responsively according to operator inputs, and that it maintains stability under various loads.
  • Monitor System Performance: After recalibration and testing, continue to monitor the hitch system closely to ensure it operates as expected without excessive speed or sensitivity.
  • Routine Maintenance and Inspections: Include regular inspections and maintenance checks of the hitch system in your ongoing maintenance routines. Frequent inspections help detect and correct minor issues before they lead to significant problems or system failures.
  • Documentation and Operator Training: Ensure that all adjustments and calibrations are documented for future reference. Provide training or guidance to operators on the importance of observing the hitch system’s performance and reporting any irregularities promptly.


Maintaining optimal deadband settings in the hitch control system is crucial for ensuring precise and efficient operation of agricultural machinery. Regular adjustments and calibrations help in preventing mechanical wear and tear and preserving the functionality and effectiveness of the hitch system, thereby enhancing the overall performance and productivity of farming operations.