ECU 005745.31 – DEF Dosing Unit Heater, Temperature Faulty. John Deere System Advisory.

ECU 005745.31 (ECU 5745.31)

Code: 005745.31

Shortcode: 5745.31


This diagnostic trouble code indicates that the on-time of the DEF dosing unit heater is faulty. This means the heater is not operating for the required duration to maintain the proper DEF temperature.


The ECU may limit or adjust the operation of the DEF dosing unit heater to manage the faulty on-time and ensure safe operation of the emissions control system.


  • Inspect DEF Dosing Unit Heater: Check for any signs of damage or wear on the DEF dosing unit heater. Replace if necessary.
  • Check Electrical Supply: Ensure that the electrical supply to the DEF dosing unit heater is stable and within specifications.
  • Test Heater Function: Use diagnostic tools to test the DEF dosing unit heater for proper operation and duration of heating cycles. Replace the heater if it is not functioning correctly.
  • Verify Timer Settings: Ensure that the timer settings for the DEF dosing unit heater are correct and functioning as intended.
  • Monitor Operating Conditions: Review the operating conditions that might contribute to faulty heater on-time, such as extreme cold weather.
  • Reset ECU and Monitor System: After resolving the issue, reset the ECU to clear the fault code and monitor the system to ensure normal operation.


Ensuring the proper operation and on-time of the DEF dosing unit heater is essential for effective DEF dosing and emissions control. Regular inspections and timely maintenance can help prevent on-time related issues.

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