ECU 005018.00 – Calculated Unintended Combustibles in DOC Extremely High. John Deere System Advisory.

ECU 005018.00 (ECU 5018.00)

Code: 005018.00

Shortcode: 5018.00


This diagnostic trouble code indicates that the ECU has detected multiple instances where the temperature differential between the Diesel Oxidation Catalyst (DOC) inlet and outlet suggests the presence of unintended combustibles within the DOC. This condition can lead to excessive temperatures and potential damage to the DOC and other exhaust components.


The ECU may limit engine performance or adjust operational parameters to prevent potential damage and manage the high levels of unintended combustibles within the DOC.


  • Inspect Fuel System: Check for issues in the fuel injection system that might cause unburned fuel to enter the exhaust stream, such as leaking injectors or incorrect injection timing.
  • Verify Combustion Efficiency: Ensure that the engine combustion process is operating efficiently. Address any issues related to incomplete combustion.
  • Inspect DOC: Check the DOC for signs of damage, blockages, or excessive soot buildup. Clean or replace the DOC if necessary.
  • Check Exhaust System: Look for any leaks or issues in the exhaust system that could allow unintended combustibles to enter the DOC.
  • Monitor Operating Conditions: Review the operating conditions and driving patterns that might contribute to the presence of unintended combustibles in the DOC.
  • Reset ECU and Monitor System: After addressing the issue, reset the ECU to clear the fault code and monitor the system to ensure temperatures and combustible levels return to normal ranges.


Proper maintenance and timely inspections of the fuel system and DOC are crucial to prevent the buildup of unintended combustibles and ensure the longevity and efficiency of the exhaust aftertreatment system.

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