John Deere 2659.01 – Engine Control Unit (ECU): NOx Based EGR Flow Correction Extremely Low / EGR Gas Flow Issue

The controller has detected that the NOx-based Exhaust Gas Recirculation (EGR) flow correction factor has reached a threshold indicating that tailpipe-out NOx is out of emissions compliance. This condition is almost always caused by heavy unburnt fuel (soot) deposits accumulating in the EGR Valve and EGR Cooler, which restricts the EGR circulation mass flow rate below normal. This is a common issue caused by prolonged "light loading" situations.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 4.5L (4045)
• 6.8L (6068)
• 9.0L (6090)
• 6105M
• DCA John Deere models

1. 1

   Review Operating Conditions: Check if the machine has been subjected to excessive idling or light loading, which prevents the engine from reaching the temperatures needed to burn off soot.

2. 2

   Check Sensor Differentials: Verify if the EGR flow measured by pressure differential is significantly higher than the EGR flow measured by temperature differential.

3. 3

   Inspect for Coolant Leaks: If the machine's history indicates coolant loss, inspect for external leaks.

4. 4

   Pressure Test the Cooling System: Pressure test the cooling system while inspecting for additional coolant buildup inside the EGR cooler. If there is no coolant loss or low coolant DTCs, do not replace the EGR cooler unless extreme soot buildup is present.

5. 5

   Check DOC Temperatures: Look for abnormally low Diesel Oxidation Catalyst (DOC) outlet temperatures during a regeneration process.

1. 1

   Access the EGR Valve

   Locate the EGR valve at the entrance of the intake manifold where exhaust gas and intake air mix.

2. 2

   Remove the EGR Valve

   Disconnect the single electrical plug and remove the 3 mounting bolts to pull the valve.

3. 3

   Inspect and Clean

   Clean off the heavy soot deposits from the EGR valve and the EGR flow venturi.

4. 4

   Inspect the EGR Cooler

   Remove the band-clamp on the cooler side to easily inspect the EGR cooler and flex piping for severe soot blockage or internal coolant leaks.

5. 5

   Replace Components (If Necessary)

   If the EGR cooler has failed a pressure test or is completely clogged beyond cleaning, install a new EGR cooler and/or EGR valve.

6. 6

   Bleed the Coolant System

   If the cooler was replaced or coolant lines were opened, ensure you bleed the coolant system at the highest engine point after repairs.

7. 7

   Load Bank / Test Run

   If a new EGR cooler is installed, it is highly recommended to run the machine under a heavy load (e.g., 2 hours of operation at 75% load) to verify engine reliability and burn off residual soot.