Case IH 3426 – ENGINE Control Module (Engine ECU): Diesel Particulate Filter (DPF): Level 1 of Particulate Filter Overloaded / Low efficiency in DPF filter / DPF Differential Pressure Too Low

The system has detected an anomaly in the exhaust backpressure. The differential pressure across the DPF is either reading too low (indicating a potential leak, sensor failure, or a missing/hollowed DPF) or the system has calculated that the filter has reached a Level 1 soot overload and is failing to regenerate efficiently.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• SR175
• SV series
• Tractors
• Farmall
• Puma
• Maxxum
• Steiger series
• F5C engine
• F5H engine

1. 1

   Inspect the differential pressure hoselines that run from the DPF to the pressure sensor for cracks, melting, blockages, or loose connections

2. 2

   Inspect the wiring harness and connector at the DPF differential pressure sensor for corrosion, shorts, or open circuits

3. 3

   Verify that the DPF has not been physically damaged, hollowed out, or removed

4. 4

   Use the Electronic Service Tool (EST) to monitor the DPF differential pressure sensor's live voltage/pressure readings while the engine is running

1. 1

   Repair/Replace Hoses

   If the diagnostic check reveals cracked, leaking, or blocked differential pressure hoses, replace them and ensure the clamps are tight.

2. 2

   Clean/Repair Connections

   If the sensor wiring is damaged, repair the harness. Clean the sensor connector with electrical contact cleaner and reconnect.

3. 3

   Perform a Forced Regeneration

   If the hoses and wiring are intact, the filter may simply be overloaded (Level 1). Use the EST diagnostic tool to command a manual/forced stationary DPF regeneration to burn off the accumulated soot.

4. 4

   Replace the Sensor

   If the forced regeneration fails, or if the sensor live data is erratic/implausible, replace the DPF Differential Pressure Sensor.

5. 5

   Clear Codes

   Clear the fault codes using the EST. Run the machine under load to verify the code does not return.

6. 6

   DPF Replacement/Cleaning

   If the code persists and the sensor/hoses are new, the DPF itself is likely internally compromised or permanently face-plugged and will require professional ash-cleaning or complete replacement.