Case IH 3429 – Engine Control Unit (ECU) / Engine Controller: Differential Pressure Hoseline Failure (e.g. Due To Leakage) - Check Hoseline Integrity. Check Sensor.

This code indicates a plausibility error detected in the Diesel Particulate Filter (DPF) differential pressure readings. The system expects a certain pressure drop across the DPF; when the reading is implausible, it assumes the hose lines connecting the DPF to the differential pressure sensor are detached, leaking (e.g., cracked or melted), or blocked.

• Farmall
• skid steer
• Skid Steer Loaders (SSL) (e.g., SV300)
• Compact Track Loaders (CTL) (e.g., TR270)
• Tractors equipped with the F5C engine (e.g., Farmall series)

1. 1

   Inspect the two hoses running from the DPF housing to the DPF Differential Pressure Sensor for signs of melting, cracking, chafing, or complete detachment

2. 2

   Disconnect the hoses and check for soot buildup or blockages inside the lines, as well as at the metal ports on the DPF itself

3. 3

   Inspect the DPF Differential Pressure Sensor's electrical connector for corrosion, pushed-out pins, or wire chafing

1. 1

   Access the DPF System

   Locate the DPF assembly and the remotely mounted DPF Differential Pressure Sensor on the engine.

2. 2

   Remove Hoses

   Carefully remove the clamps securing the differential pressure hoses to the DPF ports and the sensor.

3. 3

   Clean Ports

   Use a pick or compressed air to ensure the metal pressure ports on the DPF are completely clear of hard soot or carbon buildup.

4. 4

   Replace Hoses (If Faulty)

   If the hoses are brittle, cracked, melted, or blocked, replace them with high-temperature OEM emissions hoses. Ensure they are routed away from direct exhaust heat to prevent future melting.

5. 5

   Replace Sensor (If Hoses are Intact)

   If the hoses and ports are in perfect condition and no leaks are found, the DPF Differential Pressure Sensor itself has likely failed internally and must be replaced.

6. 6

   Clear Codes and Test

   Use the EST (Electronic Service Tool) to clear the 3429 fault code. Perform a forced DPF regeneration or a loaded test run to ensure the ECU registers the correct differential pressure and the code does not return.