BCU 523811.12 – Current Detected When Y73 Solenoid for PTO Speed 1 is Off. John Deere System Advisory.

BCU 523811.12 (BCU )

Code: 523811.12



Diagnostic trouble code BCU 523811.12 is activated when the power module PC5 detects a current exceeding 1 amp in lead 7063, despite the Y73 solenoid for PTO (Power Take-Off) Speed 1 being switched off. This abnormal current flow typically indicates a short in the circuit or an internal fault within the power module itself, potentially leading to overheating, damage to electrical components, and increased risk of fire.


The power module likely initiates its protective measures, which may include shutting down the affected circuit to prevent further damage. The system may also alert the operator to the fault through diagnostic indicators or warning messages.


  • Inspect Wiring and Connectors: Thoroughly examine the wiring and connectors associated with lead 7063 for signs of damage, wear, or improper connections that might be causing the short circuit.
  • Test for Short to Ground: Use a multimeter to test the circuit for continuity and to locate any potential short to ground. Focus on identifying the specific locations where shorting may occur.
  • Replace or Repair Damaged Components: If specific areas of damage or malfunction are identified, replace or repair the faulty wiring or components to resolve the short circuit issue.
  • Check Power Module Integrity: Ensure that the power module PC5 itself is not the source of the fault. If the module is damaged, it may need testing or replacement.
  • Reset and Test the System: After repairs are made, reset any associated fault codes and test the system to ensure that the issue has been resolved and that the current remains within safe operational limits.


Regular maintenance and proactive checks of the vehicle’s electrical systems are crucial for identifying and rectifying issues such as shorts and unexpected current conditions. Early detection and correction of electrical faults help maintain the safety and efficiency of operations, thereby extending the life of the equipment. Addressing such issues promptly is key to minimizing downtime and ensuring that the PTO system remains operational and effective.

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