ECU 004766.15 – DOC Outlet Temperature Slightly High. John Deere System Advisory.

ECU 004766.15 (ECU 4766.15)

Code: 004766.15

Shortcode: 4766.15


This diagnostic trouble code indicates that the Diesel Oxidation Catalyst (DOC) outlet temperature is detected to be slightly high. While not immediately critical, slightly elevated outlet temperatures can indicate potential issues within the exhaust system or engine operation.


The ECU may adjust engine performance or operational parameters to manage the slightly high DOC outlet temperature, aiming to maintain optimal exhaust system function and emissions control.


  • Inspect Fuel System: Check for issues in the fuel injection system that might cause slightly higher exhaust temperatures, such as excessive fuel injection or improper combustion.
  • Verify Combustion Efficiency: Ensure that the engine combustion process is operating efficiently. Address any issues related to incorrect air-fuel ratios or malfunctioning injectors.
  • Inspect Exhaust System: Look for blockages or restrictions in the exhaust system that could contribute to elevated temperatures.
  • Check DOC Condition: Inspect the DOC for any signs of early wear or blockages that might cause higher outlet temperatures.
  • Monitor Operating Conditions: Review the operating conditions and driving patterns that might contribute to slightly elevated DOC outlet temperatures.
  • Reset ECU and Monitor System: After addressing the issue, reset the ECU to clear the fault code and monitor the system to ensure temperatures return to normal ranges.


Maintaining appropriate DOC outlet temperatures is crucial for the efficiency and longevity of the exhaust aftertreatment system. Regular maintenance and timely inspections can help prevent temperature-related issues.

Control Units: John Deere

John Deere Parts
John Deere Logo