ECU 003936.16 – Calculated Unintended Combustibles in DPF Moderately High. John Deere System Advisory.

ECU 003936.16 (ECU 3936.16)

Code: 003936.16

Shortcode: 3936.16


This diagnostic code is set when the ECU detects that the level of unintended combustibles in the Diesel Particulate Filter (DPF) is moderately higher than expected. This situation indicates that some combustibles are not being fully oxidized, which can affect the efficiency of the aftertreatment system and potentially pose safety risks.


The ECU may adjust the regeneration process or limit engine performance to manage the presence of unintended combustibles, potentially leading to reduced performance to ensure emissions compliance and safety.


  • Inspect Exhaust and Aftertreatment Systems: Check the DOC and DPF for any blockages, damage, or malfunctions that could lead to the presence of unintended combustibles.
  • Verify Combustion Efficiency: Ensure that the engine is running efficiently with proper combustion, and that fuel quality meets specifications.
  • Check for Leaks or Contaminants: Inspect the exhaust system for leaks or contaminants that could contribute to the presence of unintended combustibles.
  • Perform Manual Regeneration: Conduct a manual regeneration to reduce the level of unintended combustibles in the DPF.
  • Reset ECU and Monitor System: After addressing the issue, reset the ECU to clear the fault code and closely monitor the system to ensure the unintended combustibles are effectively managed.


Promptly addressing unintended combustibles in the DPF is crucial for maintaining the safety and efficiency of the emission control system. Regular maintenance and inspections can help prevent such issues.

Control Units: John Deere

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