ATC 000168.04 – Control Unit Supply Voltage Too Low. John Deere System Advisory.

ATC 000168.04 (ATC 168.04)

Code: 000168.04

Shortcode: 168.04


This error code, ATC 000168.04, is triggered when the control unit detects a supply voltage below the normal operational threshold, specifically less than 9 volts. This low voltage condition was identified at pin 22, lead 0402, ELX. A voltage level this low can impair the functionality of the electronic components, leading to reduced efficiency or failure of the equipment’s electrical systems.


Upon detecting a low voltage condition, the control unit may activate a safety mode, limiting or halting certain functions to protect the system’s integrity. This preventive measure helps prevent malfunctions that could arise from inadequate power supply.


  • Inspect Battery and Charging System: Check the battery’s health and the charging system’s functionality. A weak battery or a failing alternator can lead to low voltage issues.
  • Verify Connections and Grounds: Ensure all electrical connections, including grounds, are tight, clean, and free of corrosion. Poor connections can significantly drop the voltage.
  • Use a Multimeter to Check Voltage Levels: Measure the voltage at pin 22, lead 0402, ELX to verify if the supply voltage is consistently below the norm.
  • Examine Voltage Regulator: Assess the voltage regulator, as it could be failing to maintain adequate voltage levels. Replace if necessary.
  • Reset Control Unit and Test System: After addressing potential issues, reset the control unit to clear the fault code and test the system to ensure it operates within the proper voltage parameters.


Maintaining correct voltage levels is crucial for the reliable operation of electrical systems in heavy machinery. Regular inspections and maintenance of the electrical components can mitigate the risk of low voltage conditions, thereby enhancing the durability and performance of your John Deere equipment.