John Deere 3251 – ECU: DPF Differential Pressure Sensor Fault

The DPF differential pressure sensor is not responding, or the controller has detected a correlation problem between the exhaust flow and the DPF differential pressure. The sensor is either failing to read the pressure difference across the DPF accurately, the sensor lines are blocked, or the DPF itself is severely restricted.

• 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
• 8R / RW Series (8245R to 8400R)
• 9RT Series (9470RT, 9520RT, 9570RT)
• 6105M
• 204L Compact 4WD Loader
• 304L Compact 4WD Loader
• 85G Excavator
• 524 P Wheel Loader
• 7400A TerrainCut
• 7500A
• 7700A
• 8000A E-Cut Hybrid

1. 1

   Confirm fault codes using diagnostic software and check for related voltage codes (e.g., 003251.03 for High Voltage or 003251.04 for Low Voltage) which point directly to electrical shorts

2. 2

   Remove and inspect the differential pressure sensor tubes connecting to the exhaust for soot blockages, condensation buildup, or cracks

3. 3

   Measure the output voltage of the DPF differential pressure sensor with a multimeter to ensure readings fluctuate appropriately with engine RPM/exhaust flow

4. 4

   Inspect the wiring harness and the sensor plug for corrosion, chafing, or loose connections

5. 5

   Check the actual condition of the DPF to determine if it is severely plugged with soot or ash

1. 1

   Clean or Replace Tubes

   If the diagnostic checks reveal blocked sensor tubes, clean them out thoroughly using compressed air or replace them if they are cracked or damaged.

2. 2

   Repair Wiring

   If corrosion or a short is found in the harness, repair the wiring or replace the pigtail connector.

3. 3

   Replace the Sensor

   If the sensor fails the multimeter test or is physically damaged, replace the DPF Differential Pressure Sensor.

4. 4

   Address the DPF

   If the sensor system is functioning but the DPF is plugged, perform a forced parked regeneration via the diagnostic software. If the soot/ash load is too high for a forced regen, the DPF must be removed and professionally cleaned or replaced.

5. 5

   Reset and Test

   After repairs are made, clear the fault codes from the ECU. Run the engine and perform a system test (or a test drive under load) while monitoring live data to confirm the ECU is accurately measuring DPF differential pressure.