John Deere 5298.01 – Engine Control Unit (ECU): DOC Efficiency Extremely Low

The Engine Control Unit has detected that the Diesel Oxidation Catalyst (DOC) is not generating enough heat, meaning its catalytic efficiency is extremely low. If the DOC outlet temperature fails to rise to the expected threshold during operation or an active regeneration, the emissions control system cannot function properly, which will eventually lead to a plugged DPF, engine derate, and loss of machine availability.

• 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
• 6090MC
• 6100MC
• 6110MC
• 6090RC
• 6100RC
• 6110RC
• 8310RT
• 8335RT
• 8360RT
• 7180
• 7280
• 7380
• 7480
• 7580
• 7780
• 7980
• D24x40 S3 Navigator HDD
• D40x55 S3 Navigator HDD

1. 1

   Check for related active codes regarding exhaust temperature sensors or the fuel dosing system (e.g., fuel dosing inlet temperature, DEF/SCR faults)

2. 2

   Monitor DOC Inlet and DOC Outlet temperature sensors using a diagnostic tool to verify they read ambient temperature when cold and scale up smoothly as the exhaust heats up

3. 3

   Inspect the exhaust piping between the engine turbocharger and the DOC inlet for severe exhaust leaks that would prevent hot gases from reaching the catalyst

4. 4

   Remove the exhaust piping at the DOC inlet and inspect the face of the Diesel Oxidation Catalyst (DOC) for severe soot face-plugging, coolant/oil contamination, or physical degradation

5. 5

   Test the exhaust fuel dosing unit (hydrocarbon doser) to verify it is not clogged and successfully injects fuel into the exhaust stream

1. 1

   Resolve Upstream Issues

   Fix any exhaust leaks and repair any active fault codes related to the fuel dosing system or intake air system first.

2. 2

   Replace Faulty Sensors

   If the diagnostic checks reveal that the DOC outlet temperature sensor is reading erratically, stuck, or out of range, replace the exhaust temperature sensor assembly.

3. 3

   Clean or Replace the Fuel Doser

   If the fuel dosing injector is coked with carbon and failing to spray fuel, clean the doser tip or replace the dosing unit.

4. 4

   Replace the DOC

   If the sensors and fuel doser are working perfectly but the DOC still fails to generate heat, the catalyst is chemically depleted or "face-plugged" and the Diesel Oxidation Catalyst must be replaced.

5. 5

   Perform a Service Regeneration

   After repairs are made, use a diagnostic tool to initiate a forced stationary exhaust filter cleaning (Service Regen). Monitor the DOC outlet temperature to ensure it reaches the required threshold for DPF regeneration.

6. 6

   Clear Codes

   Once the regeneration is successful, reset the ECU to clear the 005298.01 fault code and restore full engine power.