ECU 004341.06 – DEF Dosing Unit Pressure Line Heater, Resistance Too Low. John Deere System Advisory.

ECU 004341.06 (ECU 4341.06)

Code: 004341.06

Shortcode: 4341.06


This code indicates that the resistance in the DEF dosing unit pressure line heater circuit is too low. Low resistance typically indicates a short to ground, which can cause the heater to malfunction or fail, potentially affecting DEF injection.


The ECU may limit DEF system operation to prevent damage, which can impact overall vehicle performance and emissions compliance.


  • Inspect Wiring and Connections: Check for any damaged, frayed, or loose wiring and connectors in the DEF dosing unit pressure line heater circuit. Repair or replace as necessary.
  • Test Heater Element: Use diagnostic tools to test the heater element for proper resistance. 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 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.


Ensuring the proper electrical function of the DEF dosing unit pressure line heater is essential for effective DEF injection, especially in cold conditions. Regular maintenance and timely repairs can help avoid resistance-related problems.

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