BCU 000168.16 – Control Unit Supply Voltage Too High. John Deere System Advisory.

BCU 000168.16 (BCU 168.16)

Code: 000168.16

Shortcode: 168.16


Error code BCU 000168.16 occurs when the Basic Control Unit (BCU) of a John Deere vehicle detects that the supply voltage has exceeded 16 volts. This condition indicates a potential overcharging scenario or a fault within the vehicle’s electrical system, such as a failing alternator or a malfunctioning voltage regulator, which could lead to excessive voltage damaging sensitive electronic components.


To protect critical electrical components and prevent potential damage, the BCU may activate warning indicators or disable certain functions to mitigate the impact of the high voltage until the issue is resolved.


  • Inspect the Alternator and Voltage Regulator: The alternator and voltage regulator are the most common sources of excessive voltage. Check these components for proper operation. A faulty regulator or alternator that fails to properly regulate the electrical system’s voltage needs to be repaired or replaced.
  • Check Wiring and Connections: Examine the wiring and connections for signs of damage, corrosion, or poor contacts that could affect voltage levels. Ensure that all connections are secure and free from corrosion.
  • Measure System Voltage: Use a multimeter to measure the voltage levels in the electrical system, particularly at the BCU’s power input, to verify the overvoltage condition.
  • Replace Faulty Components: If diagnostic testing identifies faulty components contributing to high voltage, replace these to avoid further risks and damage.
  • Reset the BCU: After repairs are completed, reset the BCU to clear any fault codes and retest the system to ensure that the voltage levels have normalized and no further high voltage warnings are present.


Maintaining the correct voltage levels within the electrical system is crucial for the longevity and reliability of your John Deere equipment’s electronic components. Regular inspections and preventative maintenance can help detect and resolve issues before they lead to more significant damage or operational failures.