BCU 002386.01 – E27 Beacon Light, Power Supply Fault at Power Module PC6. John Deere System Advisory.

BCU 002386.01 (BCU 2386.01)

Code: 002386.01

Shortcode: 2386.01


Error code BCU 002386.01 is triggered when the Power Module (High Frequency) PC6 in a John Deere vehicle detects a supply voltage of less than 3 volts at the output for the beacon light (lead 0732) while the beacon light is switched on. This low voltage condition typically suggests a power supply issue, which could be due to poor wiring connections, degraded wires, or faults within the power module itself, affecting the proper functioning of the beacon light.


The system may respond to this low voltage by disabling the beacon light to prevent operation under inadequate power conditions, which could lead to improper lighting performance or damage to the electrical components.


  • Inspect Wiring and Connections: Examine the wiring and connections from the power module PC6 to the beacon light. Look for any signs of damage, wear, or corrosion that might be causing the low voltage issue.
  • Test Power Module Output: Measure the voltage output at lead 0732 using a multimeter while the beacon light is activated. This test will help confirm the low voltage condition and aid in pinpointing the cause.
  • Check Ground Connections: Ensure that all ground connections related to the beacon light and power module PC6 are secure and free from corrosion. A poor ground can result in low voltage readings.
  • Replace or Repair Faulty Components: If any components of the wiring or power module are found to be defective, repair or replace them to ensure reliable power delivery to the beacon light.
  • Verify Current Draw Post-Repair: After repairs are made, measure the current draw of the beacon light to ensure that it meets the expected operational range and that the beacon light is functioning correctly.
  • Reset the Power Module and Clear Diagnostic Codes: Reset the power module PC6 to clear any diagnostic trouble codes and retest the system to ensure the beacon light operates correctly without further issues.
  • Monitor System Operation: Keep an eye on the beacon light to ensure no further issues of low voltage or open circuit arise, confirming the stability and reliability of the repairs.


Regular inspections and maintenance of vehicle lighting systems are crucial to ensure they function efficiently and reliably. In the case of beacon lights, which are essential for safety and operational effectiveness, addressing issues promptly can prevent larger system failures and ensure ongoing visibility for the operator. By maintaining electrical integrity, the risk of operational disruptions and potential safety hazards is minimized.