John Deere 4795 – ECU: DPF Missing or Not Detected

The Engine Control Unit (ECU) has detected an excessively low pressure differential across the Diesel Particulate Filter (DPF). This indicates that the pressure difference between the DPF inlet and outlet is below the expected range, leading the system to interpret that the DPF is either physically missing, internally damaged, or that the sensing circuit has failed.

• 5E
• 6E
• 6M
• 6R
• 7R
• 8R
• 8RT
• 8RX
• 9R
• 9RT
• 9RX
• R40xx
• combines
• construction equipment
• forestry models
• 4045 series engines
• 6068 series engines

1. 1

   Visually inspect the DPF housing and exhaust system for obvious signs of physical damage.

2. 2

   Inspect the two DPF differential pressure hoses for cracks, leaks, disconnections, or blockages.

3. 3

   Check the DPF differential pressure sensor and its electrical connector for damage, corrosion, or loose connections.

4. 4

   Test the DPF differential pressure sensor's voltage output with the key on and engine off (should be between 0.44 and 0.56 volts).

5. 5

   If possible, remove and visually inspect the DPF internals for physical damage, such as holes or cracks in the filter substrate.

1. 1

   Address hose issues

   If any leaks, cracks, or blockages are found in the differential pressure hoses, replace them. Ensure the hoses are correctly routed and securely connected to both the DPF ports and the sensor.

2. 2

   Replace DPF differential pressure sensor

   If the sensor has an incorrect voltage reading or visible damage, disconnect the batteries and replace the sensor. Reconnect the batteries and use a diagnostic tool to clear active fault codes.

3. 3

   Replace the DPF unit

   If the DPF is found to be damaged internally (e.g., holes or cracks allowing exhaust to pass without resistance), replace the unit. Perform a service regeneration or calibration using diagnostic software after replacement.

4. 4

   Verify the repair

   Operate the machine through multiple drive cycles to ensure the fault code does not reappear.