New Holland ENG 3429 – Engine Control Unit (ECU): Diesel Particulate Filter (DPF) Pressure sensor: Hose line Plausibility Error

The Engine Control Unit has detected a pressure variance that falls outside the acceptable pressure range. This is a plausibility error meaning the readings from the DPF differential pressure sensor do not align with expected operating parameters, which is a primary indication of a cracked, clogged, melted, or improperly installed differential pressure sensor hose line.

• L220
• L225
• L230
• C232
• C238
• SR175
• T4.75
• T4.85
• T4.95
• T4.105
• T4.115
• T4.80V
• T4.100F
• T5.95
• T5.105
• T5.115
• TK4 series
• B90B
• B100B
• B110C
• B95C
• U80C

1. 1

   Visually inspect the differential pressure hoses connecting the DPF to the pressure sensor for cracks, melting from exhaust heat, chafing, or complete disconnection.

2. 2

   Verify that the air lines leading to the sensor are not clogged with soot or debris.

3. 3

   Inspect the differential pressure sensor itself to ensure it is not physically damaged or improperly installed.

4. 4

   Perform a leak down or smoke test on the hose lines to check for micro-leaks if visual inspection yields no obvious cracks.

1. 1

   Locate the DPF Differential Pressure Sensor

   Find the sensor, which is typically mounted on the chassis or engine block near the DPF assembly, connected by two distinct hoses/tubes to the DPF canister.

2. 2

   Remove the Hoses

   Carefully disconnect the hoses from both the DPF ports and the sensor ports.

3. 3

   Clear the DPF Ports

   Ensure the metal ports on the DPF itself are not clogged with hard soot. Carefully clear them with a pick or compressed air if necessary.

4. 4

   Replace Hoses (If Damaged)

   If the hoses are cracked, brittle, or melted, replace them with OEM rigid tubes/hoses. Ensure they are routed correctly away from direct exhaust heat to prevent future melting.

5. 5

   Replace the Sensor (If Hoses are Intact)

   If the hoses are in perfect condition and clear of blockages, the plausibility error is likely due to a failed internal diaphragm in the differential pressure sensor. Replace the sensor.

6. 6

   Clear Codes and Regenerate

   Use a diagnostic scan tool to clear the ENG 3429 fault code. Run a manual/parked DPF regeneration to verify the sensor is reading differential pressure correctly and that the code does not return.