BCU 523691.00 – Lower Worklights on Cab Frame, Current Overload Protection Active. John Deere System Advisory.

BCU 523691.00 (BCU )

Code: 523691.00



Error code BCU 523691.00 is activated when the Power Module (High Frequency) PC6 in a John Deere vehicle detects a total amperage exceeding 40 amps at the A1, C1, and D1 outputs, which are associated with several critical functions. This diagnostic trouble code is indicative of a short to ground or a defective component within the circuits connected to these outputs, affecting the lower worklights on the cab frame, the compressor clutch, and the beacon light, among others. The excessive current draw triggers the system’s overload protection to prevent potential damage or fire hazards from overheating.


The overload protection mechanism may disable the affected circuits to mitigate the risk of damage. This could lead to the temporary loss of functionality for the lower worklights, compressor clutch, and beacon light, potentially impacting the vehicle’s operational capabilities and safety features.


  • Inspect Affected Components and Wiring: Check all components connected to the A1, C1, and D1 outputs. Look for signs of damage, wear, or corrosion on the lower worklights, compressor clutch, and beacon light. Pay special attention to wiring and connectors that might be susceptible to shorts or overheating.
  • Measure Current Draw: Use a clamp meter to measure the current draw at each of the affected outputs to identify which component or circuit is drawing excessive current.
  • Identify and Repair Short Circuits: Locate and repair any shorts to ground or replace defective components that are contributing to the high amperage draw. Ensure all repairs adhere to manufacturer specifications to prevent future issues.
  • Reset the Power Module PC6: After addressing the underlying issues, reset the power module to clear the error codes and deactivate the overload protection. This will restore functionality to the disabled circuits.
  • Test All Functions Post-Repair: Thoroughly test all functions associated with the A1, C1, and D1 outputs to ensure they operate correctly and safely under normal conditions. Verify that the current draw remains within safe limits.
  • Monitor System Operation: Continue monitoring the system to ensure that no further overload conditions occur. Regular checks can help identify potential issues before they result in system failures.


Regular maintenance and proactive monitoring of electrical systems in heavy equipment are essential to prevent overloads and ensure safe operation. By maintaining electrical components in good working condition and promptly addressing any signs of overload or damage, operators can avoid operational disruptions and extend the lifespan of the vehicle’s systems.