BCU 523760.04 – Supply Voltage Too Low for Turn Signal/Hazard Flasher System. John Deere System Advisory.

BCU 523760.04 (BCU )

Code: 523760.04



The diagnostic trouble code BCU 523760.04 is generated when the Body Control Unit (BCU) detects a supply voltage of less than 12 volts at the inputs for the turn signal/hazard flasher system. This low voltage condition indicates a potential issue within the vehicle’s electrical system that could affect the functionality and reliability of the turn signals and hazard flashers, crucial for safe operation and signaling on the vehicle.


Upon detecting this low voltage, the system may limit or alter the functionality of the turn signals and hazard flashers to prevent erratic performance, and an alert may be issued to the operator to check the electrical system.


  • Inspect Battery and Charging System: Ensure that the battery is fully charged and functioning properly. Check the vehicle’s charging system for issues that could lead to low voltage outputs.
  • Check Wiring and Connections: Examine the wiring and connections to the turn signal/hazard flasher system. Look for loose connections, corroded terminals, or damaged wires that could contribute to voltage drops.
  • Test Supply Voltage: Use a multimeter to measure the voltage at the inputs of the turn signal/hazard flasher system to verify that they receive adequate voltage.
  • Replace or Repair Faulty Components: If specific components or sections of wiring are identified as faulty or underperforming, repair or replace them to ensure the correct operation of the electrical system.
  • Reset the System and Re-test: After any necessary repairs, reset any associated systems and retest the turn signals and hazard flashers to ensure they operate correctly at the proper voltage level.


Regular maintenance of the vehicle’s electrical system, including the battery and alternator, is crucial to prevent issues like low voltage. Ensuring all electrical components are in good working order enhances the reliability and safety of the vehicle, particularly in signaling systems that play a critical role in communication with other road users.