ECU 003031.03 – DEF Tank Fluid Temperature Signal Out of Range High. John Deere System Advisory.

ECU 003031.03 (ECU 3031.03)

Code: 003031.03

Shortcode: 3031.03


This error code occurs when the Diesel Exhaust Fluid (DEF) tank fluid temperature signal exceeds the upper limit, likely due to a short to 12 volts. This may result in incorrect temperature readings, affecting DEF fluid management and emission control systems.


The control system may take corrective actions based on erroneous high temperature readings, potentially affecting DEF usage and emission reductions.


  • Inspect Temperature Sensor and Wiring: Check the DEF tank temperature sensor and associated wiring for signs of damage or shorts to power sources.
  • Measure Sensor Voltage: Confirm the voltage at the temperature sensor matches the expected specifications. High voltage readings indicate a short to 12 volts.
  • Replace Damaged Sensor or Wiring: Correct any electrical issues found during the inspection by repairing or replacing the temperature sensor or wiring.
  • Reset ECU and Re-calibrate System: After repairs, reset the ECU to clear the fault and recalibrate the system to ensure accurate temperature readings.


Accurate DEF temperature measurement is essential for proper DEF fluid management and compliance with emission standards. Regular checks can prevent errors that might lead to emission system failures.

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