How to Clean a Diesel Particulate Filter (DPF) Safely

Introduction

A diesel particulate filter (DPF) is designed to trap soot and harmful particles in your exhaust system, protecting both your engine and the environment. Over time, the filter can become clogged, which leads to reduced performance, higher fuel consumption, and dashboard warning lights.
👉 Regular cleaning and regeneration cycles can extend the life of your DPF and save you thousands compared to replacement.

Signs Your DPF Needs Cleaning

  • Loss of power or sluggish acceleration

  • Reduced fuel economy

  • DPF warning light on the dashboard

  • More frequent regenerations than normal

Cleaning Methods

1. Passive & Active Regeneration

Most modern trucks — including Freightliner and other Class 8 models — use automatic diesel particulate filter regeneration. This burns soot off at high temperatures while driving (passive) or when exhaust temps rise with extra fuel injection (active).

2. Forced Regeneration (Manual Regen)

When the filter is too clogged for automatic cleaning, mechanics use dealer-level diagnostic software (like Cummins Insite, Detroit DDDL, JPRO, or Volvo Tech Tool) to trigger a regen cycle. This process heats the filter and clears soot safely, restoring performance.

3. Off-Truck Professional Cleaning

In severe cases, the DPF may need to be removed and cleaned with specialized diesel DPF cleaner equipment. This deep cleaning service restores the filter without replacement and keeps the truck compliant with emissions standards.

Step-by-Step: Running a Forced Regen

  1. Park the vehicle in a safe, ventilated area.

  2. Connect your diagnostic laptop and adapter (e.g., Nexiq USB Link 3).

  3. Open the software (Cummins Insite, Detroit DDDL, etc.).

  4. Initiate a forced regeneration cycle.

  5. Monitor exhaust temperatures and soot levels until the regen is complete.

👉 Heavy Diagnostic laptops come preloaded with the software you need to run forced regens whenever required — putting dealer-level control in your hands.

Conclusion

A clogged diesel DPF filter doesn’t always mean costly replacement. Using proper regeneration methods or professional cleaning, you can extend filter life, improve engine efficiency, and avoid downtime.
Important: Always follow manufacturer guidelines and EPA regulations. Proper DPF maintenance not only saves money but also ensures your truck stays road-legal and emissions-compliant.

Back to blog