New Holland ENG 3789 – Engine Control Unit (ECU): Diesel Particulate Filter (DPF): To check if regeneration duration exceeds maximum allowed duration.

The Engine Control Unit has detected that an active DPF regeneration cycle did not complete within the maximum allowable time limit. This typically means the system is unable to burn off the accumulated soot efficiently, which is usually caused by exhaust restrictions, a faulty differential pressure sensor providing inaccurate readings, damaged sensor hoses, or a DPF that is overloaded with incombustible ash.

• L225
• L230
• C232
• C238
• W50C
• W60C
• W70C
• W80C
• T4.75
• T4.95
• T6
• T7
• T8
• T9
• TD5.115
• CR9090
• CX8080
• CX8090

1. 1

   Inspect the entire exhaust line for physical damage, crushed pipes, or blockages that could restrict exhaust flow.

2. 2

   Visually inspect the high-temperature silicone hoses connecting the DPF to the differential pressure sensor. Look for blockages (soot buildup), melting, cracks, or rodent damage. Ensure they are securely attached and not swapped.

3. 3

   Use a diagnostic tool to monitor the DPF differential pressure sensor voltage and pressure readings with the engine off (should read zero) and while running. Implausible pressure drops indicate a failed sensor or blocked line.

4. 4

   Check the machine's operating hours and the calculated DPF ash load in the ECU. If the DPF has exceeded its service life for ash accumulation, regeneration will no longer be effective.

1. 1

   Repair/Replace Hoses

   If the differential pressure sensor hoses are cracked, blocked, or damaged, replace them using high-temperature silicone emissions hose.

2. 2

   Replace the Sensor

   If the hoses are intact but the sensor readings are erratic or out of range, replace the DPF Differential Pressure Sensor.

3. 3

   DPF Service

   If the sensor and hoses are functioning correctly, the DPF is likely face-plugged or full of ash. Remove the DPF assembly and send it to a certified DPF cleaning facility for pneumatic/thermal ash removal, or replace the DPF entirely.

4. 4

   Clear Codes

   Reconnect all components and use a New Holland Electronic Service Tool (EST) to clear the ENG 3789 fault code.

5. 5

   Forced Regeneration

   Perform a manual/service regeneration via the diagnostic tool to verify the repair. Monitor the regeneration timer to ensure the cycle completes successfully within the normal time parameters.