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

BCU 523756.18 (BCU )

Code: 523756.18



Diagnostic trouble code BCU 523756.18 is triggered when the lowering deadband—defined as the clearance between the adjustment cam of the stepper motor and the lower valve of the hitch valve—is found to be excessively low during calibration. This limited clearance can result in mechanical interference, which might cause premature wear of the components or affect the smooth operation of the hitch, leading to inefficient and potentially unstable hitch control.


The BCU may limit or adjust the operation of the hitch to prevent damage due to the insufficient deadband. Alerts or warnings may be triggered to inform the operator of the need for recalibration to address this issue.


  • Inspect Mechanical Linkages and Settings: Check the mechanical linkages between the stepper motor and the hitch valve. Assess for signs of excessive wear or misalignment that could reduce the deadband.
  • Increase Deadband to Recommended Levels: Adjust the position of the adjustment cam or related mechanical components to increase the deadband to within the manufacturer’s recommended specifications.
  • Calibrate the Hitch System: Recalibrate the hitch system following any adjustments to ensure that the changes have been correctly implemented and that the system operates efficiently.
  • Perform Operational Tests: Test the hitch through its full range of motion to confirm that the hitch responds appropriately to controls and that the issue of a too-low deadband has been resolved.
  • Maintain Regular Checks: Establish a routine maintenance protocol to regularly assess and adjust the hitch mechanism, ensuring that mechanical clearances remain within optimal ranges.


Proper maintenance and calibration are crucial for the efficient operation of agricultural machinery. Regularly addressing calibration issues, such as adjusting deadband settings, helps ensure that equipment operates reliably and effectively, reducing the risk of mechanical failures and enhancing overall performance and safety.