CRU 000168.03 – High Supply Voltage Detected in Control Software. John Deere System Advisory.

CRU 000168.03 (CRU 168.03)

Code: 000168.03

Shortcode: 168.03


This error code, CRU 000168.03, indicates that the radio unit (CRU) has detected an unswitched supply voltage exceeding 18 volts. This condition suggests a potential issue with the voltage regulation or electrical system supplying power to the unit. High voltage levels can damage electronic components and impair the functionality of the control software.


The control software may operate with limited functionality or may cease to function entirely to protect the system from potential damage caused by excessive voltage.


  • Diagnose Voltage Regulator and Electrical Connections: Start by checking the voltage regulator and the connections supplying power to the CRU. Look for signs of damage, wear, or incorrect installation that could contribute to excessive voltage levels.
  • Inspect and Test Battery and Alternator: Ensure the battery and alternator are functioning properly. An overcharging alternator or a malfunctioning battery could be responsible for high voltage outputs.
  • Use a Multimeter to Verify Voltage Levels: Measure the voltage levels at various points in the electrical system, especially at the radio unit, to confirm that they are within the specified limits.
  • Check for Faulty Wiring or Ground Issues: Examine the wiring harness for any signs of damage, corrosion, or poor grounding that could affect voltage stability.
  • Reset the Control Software and Re-test: After making any necessary repairs, reset the control software to ensure all protective measures are removed. Re-test the system to verify that the voltage levels are now within normal operational limits.


Maintaining proper voltage levels is crucial for the reliable operation of electronic control systems. Regular checks and maintenance of the electrical system can prevent issues related to overvoltage and ensure the longevity and effectiveness of the control software. Promptly addressing high voltage issues is essential to avoid long-term damage to the equipment.

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