BCU 303057.04 – B27 Rate of Drop Potentiometer, Signal Voltage Too Low. John Deere System Advisory.

BCU 303057.04 (BCU )

Code: 303057.04



Error code BCU 303057.04 occurs when the Basic Control Unit (BCU) of a John Deere vehicle measures a voltage below 0.25 V at the signal input of the B27 rate of drop potentiometer during the calibration of the hitch control. This low voltage reading can indicate issues such as poor connections, broken wiring, or a faulty potentiometer, potentially affecting the calibration and function of the hitch’s rate of drop adjustment.


The system may interrupt the calibration process or display errors concerning the hitch control settings, as the incorrect voltage could lead to inaccurate adjustment of the hitch’s rate of drop, potentially affecting the vehicle’s operational efficiency and safety.


  • Inspect the Rate of Drop Potentiometer: Examine the potentiometer for signs of physical damage or deterioration. Check that it is installed correctly and that connections are secure and intact.
  • Check Wiring and Electrical Connections: Assess the wiring leading to the potentiometer for signs of damage, corrosion, or loose connections that might be causing the low voltage readings.
  • Measure Voltage at Signal Input: Use a multimeter to verify the low voltage at the potentiometer’s signal input to diagnose the issue accurately.
  • Repair or Replace Faulty Components: If the potentiometer is faulty or if any wiring issues are identified, repair or replace these components to ensure proper functionality and accurate voltage transmission.
  • Recalibrate the Hitch Control System: After repairs or component replacement, recalibrate the hitch control system according to the manufacturer’s guidelines to ensure all settings are correctly adjusted.
  • Reset the BCU and Clear Diagnostic Codes: Reset the BCU to clear any error codes and to acknowledge the repairs, helping reinitialize the system’s settings.
  • Monitor System Operation Post-Repair: Continuously monitor the hitch control system after the repair to ensure that the potentiometer functions correctly and maintains appropriate voltage levels during operation.


Maintaining the accuracy of control system components such as the rate of drop potentiometer is essential for the precision operation of farm machinery. Regular inspections and timely repair of components play a crucial role in preventing operational failures and ensuring the machinery performs optimally. Effective maintenance not only extends the life of the equipment but also ensures it operates safely and efficiently, minimizing potential risks in the field.