BCU 001873.04 – Hitch Position Sensor Low Voltage Error. John Deere System Advisory.

BCU 001873.04 (BCU 1873.04)

Code: 001873.04

Shortcode: 1873.04


Error code BCU 001873.04 is triggered when the Basic Control Unit (BCU) of a John Deere vehicle detects an abnormally low voltage (below 0.25 volts) at the input of the hitch position sensor. This low voltage reading indicates a potential issue in the sensor circuit, such as a poor connection, broken wire, or a fault within the sensor itself, which could impair the accurate monitoring and control of the hitch position.


The BCU may respond to this fault by displaying a warning on the vehicle’s dashboard and potentially restricting hitch operation to prevent unintended movements that could result from incorrect sensor readings.


  • Inspect Hitch Position Sensor and Wiring: Examine the hitch position sensor for any signs of physical damage or deterioration. Check the wiring and connectors for breaks, corrosion, or looseness that could be causing the low voltage.
  • Measure Voltage Output: Use a multimeter to test the voltage at the sensor input to confirm the low voltage condition. This will help identify if the issue is localized at the sensor or elsewhere along the circuit.
  • Repair or Replace Wiring: If damaged wiring or connectors are found, repair or replace them to ensure a stable and adequate voltage supply to the sensor.
  • Replace Faulty Sensor: If the hitch position sensor is found to be faulty after testing, replace it to restore accurate function and reliable operation of the hitch system.
  • Test System Functionality: After addressing the issues, conduct a full test of the hitch system to ensure it operates correctly under various conditions and the sensor now provides accurate readings.
  • Reset the BCU and Clear Diagnostic Codes: Clear any fault codes from the BCU and reset the system to ensure that all systems are functioning without interference and that the repair was successful.


Maintaining the integrity of sensor inputs is crucial for the precise operation of agricultural machinery. Regular checks and prompt repair of sensors and electrical circuits help ensure that your John Deere equipment operates efficiently and safely. Proper diagnostics and maintenance of the hitch position sensor are essential for reliable hitch performance, minimizing downtime and maximizing productivity.