John Deere ECU003936.00 – ECU: Unexpected Temperature in Exhaust Filter

The Engine Control Unit (ECU) has detected an abnormal temperature differential between the Diesel Oxidation Catalyst (DOC) outlet and the DPF outlet, indicating the presence of unintended combustibles within the Diesel Particulate Filter (DPF). As a result, engine power is limited and the active exhaust filter cleaning function is disabled to prevent damage. Continued operation may lead to a significant loss of machine availability.

• 9470RT
• 9520RT
• 9570RT
• 7180
• 7280
• 7380
• 7480
• 7580
• 7780
• 7980
• 3032E
• 3038E
• 5055E
• 6190R
• 4045HFC92

1. 1

   Inspect the wiring harness and connectors for the exhaust temperature sensors (often located on the firewall behind the engine) for rodent damage, chafing, or corrosion, and ensure they are fully seated and free of contamination

2. 2

   Inspect the exhaust system for any blockages or obstructions that could cause abnormal temperature readings

3. 3

   Use a voltmeter to verify that there is a 5-volt power supply to the exhaust temperature sensors

4. 4

   Attempt to initiate a manual or parked regeneration of the DPF through the tractor's display menu to clear potential soot buildup

5. 5

   Review operating habits, as extended periods of low engine speed (below 1500 rpm) or low engine load can lead to soot buildup and trigger this fault

1. 1

   Repair wiring and obstructions

   If any wiring damage, exhaust obstructions, or power supply issues were found during the diagnostic checks, repair them before proceeding.

2. 2

   Test exhaust gas temperature sensors

   Use a diagnostic tool to monitor live data from the exhaust gas temperature sensors for plausible readings. Test the sensor's resistance at room temperature and when heated to ensure correct functionality.

3. 3

   Replace faulty temperature sensor

   If a sensor (DOC inlet, DPF inlet, or DPF outlet) is determined to be faulty, replace it with the correct part for your specific machine.

4. 4

   Service or replace DPF

   If the fault persists after sensor replacement, the Diesel Particulate Filter (DPF) may require professional service cleaning or complete replacement.