BCU 303056.03 – B27 Raise Limit Potentiometer, Signal Voltage Too High. John Deere System Advisory.

BCU 303056.03 (BCU )

Code: 303056.03



Error code BCU 303056.03 is triggered when the Basic Control Unit (BCU) of a John Deere vehicle detects a voltage exceeding 4.75 V at the signal input of the B27 raise limit potentiometer during the calibration of the hitch control. This high voltage reading can indicate a malfunction within the potentiometer or its associated wiring, potentially leading to incorrect settings in the hitch control system.


The calibration process may be disrupted by this error, which could result in improper adjustment of the hitch’s raise limit. Such an error might affect the tractor’s operational capabilities and can lead to suboptimal agricultural performance or mechanical strain on the hitch system.


  • Inspect the Raise Limit Potentiometer: Check the B27 potentiometer for signs of damage or malfunction. Ensure it is properly installed and connected.
  • Examine Wiring and Connections: Look over the wiring connections to the potentiometer. Search for potential issues such as frayed wires, loose connections, or corrosion at contact points that could result in abnormal voltage readings.
  • Verify Voltage Levels: Use a multimeter to measure the voltage at the potentiometer’s signal input. Confirm that the voltage exceeds the normal range to validate the diagnostic trouble code.
  • Replace or Repair Faulty Potentiometer: If the potentiometer is found to be faulty, replace it to ensure accurate voltage measurement and proper functionality.
  • Recalibrate Hitch Control: After replacing the potentiometer, recalibrate the hitch control system to ensure that all settings are correctly adjusted according to the new component specifications.
  • Reset the BCU and Clear Diagnostic Codes: Reset the BCU to clear the error code and acknowledge the replacement and recalibration. This step will also help to reinitialize the system’s settings.
  • Monitor Hitch Operation Post-Repair: Continuously monitor the operation of the hitch system after the repair to ensure that the new potentiometer maintains appropriate voltage levels during use and that no further issues occur.


Maintaining the correct functionality of components like the raise limit potentiometer is crucial for precision in farm equipment operation. Regular inspections and immediate responses to issues are essential to avoid operational delays and ensure that machinery performs efficiently and safely. Such proactive maintenance not only preserves the machinery’s longevity but also ensures it operates within safe and optimal parameters.