DSM 000168.03 – Control Unit Supply Voltage Too High. John Deere System Advisory.

DSM 000168.03 (DSM 168.03)

Code: 000168.03

Shortcode: 168.03


This diagnostic trouble code (DSM 000168.03) indicates that the control unit has detected a supply voltage exceeding 16 volts. This situation can arise due to issues within the electrical system, such as a faulty alternator or voltage regulator, or problems with the wiring harness.


When the supply voltage exceeds 16 volts, the control unit may take protective measures to prevent damage to sensitive components. This could include limiting certain functionalities or shutting down specific systems to prevent overvoltage damage.


  • Inspect Electrical System: Examine the alternator and voltage regulator for signs of malfunction. Ensure that they are operating within specified voltage ranges.
  • Check Wiring Harness: Inspect the wiring harness for any signs of damage, corrosion, or loose connections that could cause an overvoltage condition.
  • Test Battery Condition: Ensure that the battery is functioning correctly and is not contributing to voltage spikes.
  • Update Control Software: Verify that the control unit software is up-to-date and configured correctly. Software updates may include fixes for voltage regulation issues.
  • Monitor Voltage Levels: Use diagnostic tools to monitor the supply voltage during operation and identify any irregularities or spikes.


Regular maintenance and monitoring of the electrical system are crucial to prevent overvoltage conditions. Addressing issues promptly can help avoid damage to the control unit and other sensitive components.

Control Units: John Deere

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