BCU 002386.12 – E27 Beacon Light Off, Current Present at Power Module PC6. John Deere System Advisory.

BCU 002386.12 (BCU 2386.12)

Code: 002386.12

Shortcode: 2386.12


Error code BCU 002386.12 is activated when the Power Module (High Frequency) PC6 in a John Deere vehicle detects a current exceeding 1 amp at the output for the E27 beacon light (lead 1004), despite the beacon light being switched off. This unexpected current flow typically indicates a short in the circuit or a potential internal fault within the power module itself, which could lead to unnecessary power consumption, potential overheating, or damage to the electrical system.


Upon detecting this condition, the system may automatically initiate safety protocols to prevent damage, potentially including disabling the power output to the beacon light to mitigate the risk of electrical fires or further damage to the power module.


  • Inspect Beacon Light and Wiring: Examine the beacon light and its wiring for any signs of damage, wear, or corrosion that could lead to a short circuit.
  • Measure Current Draw: Use a multimeter to measure the current draw at lead 1004 when the beacon light is off to confirm the excessive current.
  • Identify and Repair Short to Ground: Locate and repair any shorts to ground identified during the inspection. This may involve tracing the wiring back to the power module, checking for pinch points, worn insulation, or improper routing.
  • Evaluate Power Module PC6: Check the power module for any signs of internal faults that might be causing unintended current flow. Consider testing or replacing the module if it is suspected to be faulty.
  • Test After Repairs: After repairs are made or components replaced, test the circuit again to ensure that the current draw is within acceptable limits and that no current flows when the beacon light is switched off.
  • Reset the Power Module and Clear Diagnostic Codes: Reset the power module PC6 to clear the diagnostic trouble codes and ensure that all repairs are recognized by the system. Confirm that the system is functioning correctly and that no further fault codes related to the beacon light are present.
  • Monitor System Operation: Continue to monitor the beacon light and the associated circuit to ensure there are no further issues of unintended current draw.


Electrical safety in vehicle systems is crucial, especially when unexpected current flows could indicate serious electrical faults. Regular checks, including inspections of wiring and electrical components, are essential to ensure that electrical systems function safely and efficiently. Promptly addressing issues like unexpected current flow helps prevent potential safety hazards and maintains the integrity and reliability of the vehicle’s electrical systems.