New Holland 3774 – Engine ECU: DPF Ash Load Exceeded Limit

The Diesel Particulate Filter (DPF) has accumulated a maximum allowable level of ash. Unlike soot (unburned fuel), which can be burned off during a standard high-temperature regeneration cycle, ash is a non-combustible byproduct of burnt soot and engine oil. Once the ash load reaches this limit, standard regeneration will no longer clear the filter and physical cleaning or replacement is required.

• T6000
• PUMA
• TS Series
• Workmaster 33
• Workmaster 35
• Workmaster 37
• Workmaster 40
• Workmaster 45
• Workmaster 55
• Boomer 33
• Boomer 35
• Boomer 37
• Boomer 40
• Boomer 45
• Boomer 50
• Boomer 55
• Farmall
• B90B
• B115B
• L213
• L215
• L216
• L316
• NEF engines

1. 1

   Use a diagnostic tool (such as the CNH E.A.SY. Diagnostic System or EST) to confirm code 3774 is active.

2. 2

   Check for accompanying DPF pressure sensor codes, such as 3775 (Monitoring of the characteristic pressure reduction - max), 3776 (Monitoring of the characteristic pressure reduction - min), or 3777 (Clogged DPF filter).

3. 3

   Ensure the issue is actually an ash limit and not just a soot accumulation issue that could be resolved by a parked or forced regeneration.

1. 1

   Cool down exhaust system

   Allow the exhaust stack and fixed hood area to cool completely. The DPF gets extremely hot during operation and regeneration, posing a severe burn hazard.

2. 2

   Remove DPF assembly

   Disconnect the exhaust piping and sensor lines, then remove the DPF assembly from the machine.

3. 3

   Clean or replace DPF

   Send the DPF to a specialized facility that uses a 'blast and bake' kiln method or liquid flushing to safely extract the ash from the cell walls, or install a new or remanufactured DPF.

4. 4

   Reinstall DPF

   Install the clean or new DPF using new gaskets and seals.

5. 5

   Reset ECU parameters

   Connect the diagnostic tool (Diagmaster / CNH EST) to the tractor. You must perform a 'DPF Soot Load Reset' and a 'DPF Regeneration Interval Time Reset' (resetting the ash accumulator) in the ECU utility functions. If this is not done, the ECU will still calculate the filter as full of ash and the code will persist.