CSC 523666.03 – High Supply Voltage at Rear Chassis Control Unit. John Deere System Advisory.

CSC 523666.03 (CSC )

Code: 523666.03



This error code CSC 523666.03 is triggered when the control software detects that the supply voltage at the input of the rear chassis control unit exceeds 16 V. This condition typically indicates a short circuit within the wiring harness, which can lead to overvoltage conditions that might damage electronic components.


The control software may restrict or disable functionality to protect the system from damage caused by high voltage.


  • Inspect Wiring Harness: Thoroughly check the wiring harness for any signs of short circuits, particularly those causing a direct connection to a higher voltage source.
  • Measure Voltage Levels: Use a voltmeter to measure the voltage at the input of the rear chassis control unit and confirm that it is within the acceptable range.
  • Repair or Replace Faulty Wiring: Identify and repair any damaged or shorted wires. Replace sections of the wiring harness if necessary to ensure proper insulation and connectivity.
  • Verify Control Unit Functionality: Test the rear chassis control unit to ensure it has not been damaged by the overvoltage condition.
  • Conduct System Tests: After repairs, reset the control system and perform tests to ensure normal operation and that voltage levels remain stable.


Regular inspection and maintenance of the wiring harness are crucial to prevent electrical faults that can lead to overvoltage conditions and potential equipment damage.

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