Case IH 3779 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Diesel particulate filter (DPF) : Diagnostic fault check for particulate filter efficiency.

The engine's aftertreatment system has detected that the DPF is not operating at its expected efficiency. This is monitored via the DPF differential pressure sensor (Delta-P sensor) and points to a blocked filter (excessive soot/ash), a cracked or damaged DPF substrate, or a faulty differential pressure sensor/circuit.

• Magnum
• Maxxum
• Puma
• Steiger
• Farmall 75C
• Farmall 105C
• Farmall 115C
• Axial-Flow 5140
• FPT N45
• FPT N67
• FPT Cursor

1. 1

   Inspect the Differential Pressure Sensor and Tubes: Check the DPF Delta-P sensor and the metal tubes/hoses connecting it to the exhaust for blockages (soot buildup), melted hoses, or exhaust leaks.

2. 2

   Check Wiring and Connections: Inspect the wiring harness and the 3-pin connector at the differential pressure sensor for corrosion, chafing, or loose connections.

3. 3

   Check for Exhaust Leaks: Inspect the exhaust system upstream of the DPF. A leak before the filter will cause a low differential pressure reading.

4. 4

   Live Data Monitoring: Connect a compatible diagnostic tool to monitor live differential pressure data and check the calculated soot/ash load.

5. 5

   Tailpipe Inspection: Check the exhaust tailpipe for black soot. Heavy black soot indicates the internal ceramic substrate of the DPF is cracked and the filter must be replaced.

1. 1

   Read and Record Data

   Connect your diagnostic tool (Case IH EST or Jaltest) to read the freeze-frame data associated with code 3779 to understand the conditions when the fault occurred.

2. 2

   Clear Sensor Lines

   If the differential pressure sensor tubes are clogged with soot, remove and carefully clean them with compressed air, or replace them if damaged.

3. 3

   Perform a Forced Regeneration

   Using the diagnostic tool, initiate a stationary/forced DPF regeneration. Monitor the temperatures and pressure sensor feedback during the process.

4. 4

   Replace the Sensor (If Applicable)

   If the sensor readings remain erratic or out of specification during the regen, replace the DPF differential pressure sensor.

5. 5

   Inspect/Replace the DPF

   If the forced regeneration fails, the code immediately returns, or the filter is physically damaged/permanently face-plugged with ash, remove the DPF assembly. The filter will need to be professionally cleaned (ash removal) or replaced with a new unit.

6. 6

   Reset ECU Accumulators

   If the DPF or the differential pressure sensor is replaced, you must use the diagnostic tool to reset the DPF ash/soot accumulators and calibrate the new sensor. Failure to do this will result in the ECU keeping the permanent fault code active.