John Deere 4795.31 – Engine Control Unit (ECU): Exhaust Filter Missing or Severely Damaged

The ECU triggers this code when the DPF differential pressure sensor reports a pressure difference of near zero across the Diesel Particulate Filter (DPF) while the engine is running under load. This indicates that the DPF substrate has been physically removed, hollowed out, shattered, or that the sensor/lines are completely failing to read the pressure.

• 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
• 5095M
• 5105M
• 6105M
• 7210R
• 7230R
• 7250R
• 7270R
• 7290R
• 7310R
• 9470RT
• 9520RT
• 9570RT
• 204L
• 304L

1. 1

   Visual Inspection of the DPF: Verify that the DPF has not been physically removed, bypassed, or tampered with (e.g., 'deleted').

2. 2

   Inspect Sensor Hoses/Tubes: Check the metal tubes and rubber hoses connecting the exhaust pipe to the DPF Differential Pressure Sensor. Look for disconnected hoses, cracks, melting, or blockages caused by soot or ice.

3. 3

   Inspect Wiring and Connectors: Check the electrical connector at the DPF Differential Pressure Sensor for corrosion, pushed-out pins, or wire chafing that could cause a loss of signal to the ECU.

4. 4

   Live Data Monitoring: Using John Deere Service ADVISOR (or a compatible scan tool), monitor the DPF Differential Pressure live data. If the value reads exactly 0.0 psi and does not fluctuate when engine RPM increases, the sensor or its pressure lines are faulty.

5. 5

   Check for Software Updates: Verify the ECU is on the latest software version, as John Deere has released ECU calibration updates for certain models specifically to address incorrect DPF detection logic and false 4795.31 codes.

1. 1

   Secure the Machine

   Park the machine on a level surface, engage the parking brake, and turn off the engine. Allow the exhaust system to cool completely to avoid burns.

2. 2

   Repair/Replace Pressure Lines

   If the diagnostic checks reveal cracked, melted, or clogged differential pressure lines, remove the damaged sections. Clear any soot blockages from the exhaust ports and install new lines. Ensure all clamps are tight so no exhaust leaks occur before the sensor.

3. 3

   Replace the Sensor (if faulty)

   If the lines are intact but the sensor fails to read pressure during live data testing, disconnect the electrical harness from the DPF Differential Pressure Sensor. Unbolt the sensor from its mounting bracket, disconnect the pressure hoses, and install the new sensor. Reconnect the hoses and electrical harness.

4. 4

   Inspect/Replace DPF Substrate (if necessary)

   If the sensor and lines are perfectly functional, the DPF substrate itself may be shattered or melted away internally. Remove the DPF canister and inspect the honeycomb substrate. If it is damaged or missing, the entire DPF assembly must be replaced.

5. 5

   Clear Codes and Test

   Connect your diagnostic tool, clear the 004795.31 fault code, and perform a stationary forced Exhaust Filter Cleaning (Regen). Monitor the differential pressure during the regen to ensure it rises to normal operating specifications, confirming the repair.