ECU 005435.06 – DEF Dosing Unit Pump Circuit Has Low Resistance. John Deere System Advisory.

ECU 005435.06 (ECU 5435.06)

Code: 005435.06

Shortcode: 5435.06


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


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


  • Inspect Wiring and Connections: Check for damaged, frayed, or loose wiring and connectors associated with the DEF dosing unit pump. Repair or replace as necessary.
  • Test DEF Pump Element: Use diagnostic tools to test the DEF dosing unit pump for proper resistance and continuity. Replace the pump 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 pump 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.


Proper electrical function of the DEF dosing unit is crucial for accurate dosing and emissions control. Regular inspections and timely maintenance can help prevent resistance-related issues.

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