BCU 523691.00 – Overcurrent Protection Triggered for Lower Worklights on Cab Frame. John Deere System Advisory.

BCU 523691.00 (BCU )

Code: 523691.00



This error code, BCU 523691.00, is generated when the power module (HF) PC6 detects an overcurrent condition, measuring total amperage in excess of 40 amps across the A1, C1, and D1 outputs. This code is associated with several functions, which are monitored together and may lead to additional diagnostic trouble codes:

  • Output A1: M02 Compressor clutch (ATC 000876.00)
  • Output C1: E27 beacon light (BCU 002386.00)
  • Output D1: E20/R and E20/L worklights on cab frame (right and left)
  • Output D1: E36R and E36L xenon (HID) worklights on cab frame (right and left) The overcurrent condition usually points to a short to ground or a defective component within one of these circuits.


Activation of current overload protection disables the outputs (A1, C1, and D1) to prevent further electrical damage or fire hazard, affecting the functionality of connected components such as worklights, compressor clutch, and beacon lights.


  • Inspect and Test All Affected Circuits: Thoroughly inspect the wiring and connections for the affected outputs. Look for signs of wear, corrosion, or damage that could lead to short circuits.
  • Replace or Repair Defective Parts: If a defective component or damaged wire is found, replace or repair it to resolve the overcurrent issue.
  • Check for Short to Ground: Perform tests to identify any short to ground issues in the circuits. This may involve using a multimeter to test resistance between the wiring and the vehicle frame.
  • Reset and Monitor the System: After repairs, reset the power module and monitor the system for recurrence of high current levels. Ensure that the total amperage stays within safe limits.
  • Review Additional Diagnostic Codes: Since this issue may trigger other related diagnostic codes, review and resolve any additional codes that have appeared as a result of this overcurrent condition.


Monitoring and maintaining electrical components in good working condition is crucial for safe operation. Regularly checking the electrical system and promptly addressing issues like overcurrent can prevent more serious damage and ensure the longevity of the vehicle’s electrical systems.