ECU 005745.06 – DEF Dosing Unit Heater, Resistance Too Low. John Deere System Advisory.

ECU 005745.06 (ECU 5745.06)

Code: 005745.06

Shortcode: 5745.06


This diagnostic trouble code indicates that the circuit resistance for the Diesel Exhaust Fluid (DEF) dosing unit heater is too low, typically indicating a short to ground. This condition can affect the proper functioning of the DEF dosing unit heater.


The ECU may limit or adjust the operation of the DEF dosing unit heater to manage the low circuit resistance and ensure safe operation of the DEF dosing system.


  • Inspect Wiring and Connections: Check for damaged, frayed, or loose wiring and connectors associated with the DEF dosing unit heater circuit. Repair or replace as necessary.
  • Test DEF Dosing Unit Heater: Use diagnostic tools to test the DEF dosing unit heater for proper resistance and continuity. Replace the heater if it is faulty.
  • Check for Short Circuits: Inspect the circuit for any points where wires may be touching ground, causing a short circuit. Repair or insulate as needed.
  • Verify Electrical Supply: Ensure that the electrical supply to the DEF dosing unit heater is stable and within specifications.
  • 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.


Maintaining proper electrical function and resistance in the DEF dosing unit heater circuit is crucial for maintaining the correct DEF temperature and ensuring effective emissions control. Regular inspections and timely maintenance can help prevent resistance-related issues.

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