ECU 005018.16 – Calculated Unintended Combustibles in DOC Moderately High. John Deere System Advisory.

ECU 005018.16 (ECU 5018.16)

Code: 005018.16

Shortcode: 5018.16


This diagnostic code is set when the calculated level of unintended combustibles within the DOC is moderately higher than expected. This condition can affect the performance of the DOC and potentially lead to higher exhaust temperatures.


The ECU may limit engine performance or adjust operational parameters to manage the moderately 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.


Maintaining the efficiency of the DOC and preventing the buildup of unintended combustibles is essential for optimal exhaust system performance and emissions compliance. Regular maintenance and timely inspections can help prevent these issues.

Control Units: John Deere

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