Your diesel particulate filter (DPF) traps soot so it doesn't leave the tailpipe. Most of that soot burns off during regeneration, but not everything does. Over time, the filter fills with material that only an off-vehicle cleaning can remove.
Here are the signs that a DPF is due for a cleaning, what to check first, and how to get your filter to our South Bend shop.
Soot vs. Ash: Why Regeneration Isn't Enough
A DPF collects two kinds of buildup:
- Soot is combustible carbon. Your engine burns it off during regeneration, the high-temperature cycle that runs on its own or when you start a parked regen.
- Ash is the noncombustible residue left mostly by engine-oil additives. It doesn't burn, so regeneration can't remove it.
Ash builds up slowly, but it doesn't go away on its own. As it fills the filter, there's less room for soot, regens come more often and backpressure climbs. At that point the filter needs to come off the truck for a professional cleaning.
1. The DPF Warning Light or Fault Codes Keep Coming Back
A DPF light that returns soon after a regen is one of the clearest signs of a loaded filter. Common fault codes include:
- P2463 – DPF restriction, soot accumulation
- P242F – DPF restriction, ash accumulation
- P244B – DPF differential pressure too high
Some codes point to a sensor problem rather than a full filter. P244A (differential pressure too low) and the P2452–P2455 pressure-sensor codes often come from a failed sensor, a cracked or plugged sensor line, or an exhaust leak, so check those parts before pulling the filter. P2002 (DPF efficiency below threshold) can mean the filter is cracked or damaged, which cleaning won't fix.
Heavy-duty engines may show manufacturer-specific codes instead. If you're not sure what a code means for your engine, call us with the code and part number.
2. Regenerations Are More Frequent or Won't Finish
If your truck regenerates far more often than it used to, or regens start but don't complete, the filter may be filling with ash. A successful regen that doesn't bring backpressure back to normal is a strong sign the filter needs a cleaning, not another regen.
3. Lost Power or Derate
A restricted filter makes the engine work harder to push exhaust out. You may notice slower acceleration, trouble holding speed on hills or under load, or the engine control module derating power to protect the system.
4. Fuel Mileage Drops
Higher backpressure and more frequent active regens both use extra fuel. A steady drop in mileage that regens don't fix is worth checking.
5. Rising Oil Level
An oil level that climbs between changes can mean fuel is diluting the oil, which can happen when active regens fail or run too often. Have it diagnosed and change the oil promptly, because diluted oil speeds up engine wear.
6. It's Been a Long Time Since the Last Cleaning
Even a truck that regenerates perfectly will eventually need its DPF cleaned. Follow your engine manufacturer's service schedule for DPF ash cleaning, and clean sooner if you see any of the signs above.
When Cleaning Won't Solve the Problem
Cleaning restores airflow through a filter that's loaded with soot and ash. It can't repair a filter that's cracked, melted or contaminated with oil or coolant. It also won't fix the cause if something upstream is overloading the filter, such as:
- Injector, turbo or EGR problems that create excess soot
- High oil consumption that adds ash faster
- A faulty pressure or temperature sensor
During our initial inspection, if we find damage such as cracks, melting or contamination, we'll contact you before going further. If your filter can't be saved, we also sell replacement diesel particulate filters and DOCs.
How We Clean Your DPF
Diesel DPF Cleaning is a Cummins-approved cleaning center and a Clean Diesel Specialists licensee. Our cleaning follows the Clean Diesel Specialists process: an initial inspection and baseline airflow reading, off-vehicle cleaning to remove soot and ash, and a final airflow and structural check before the filter goes back to you. See our full cleaning process.
- DPF cleaning: $300, with 24-hour turnaround once your filter arrives
- DOC cleaning: $80 when cleaned with a DPF, or $300 on its own
- EGR cooler cleaning: $300, with 48-hour turnaround
Getting Your Filter to Our South Bend Shop
- Drop off and pick up: bring your filter to our cleaning plant at 215 Ullery St, Unit 2, South Bend, IN 46637 and save $25 on each item when you pick it up from the plant.
- Free pickup and delivery: available for DPF cleaning within 90 miles of our cleaning plant, including Mishawaka, Elkhart, Goshen, Niles, LaPorte, Michigan City and Kalamazoo. See our pickup area and drop-off guide.
- Ship it in: call first and we'll help you get it here.
When you reinstall the filter, use new gaskets and clamps. We carry DPF gaskets and clamps, plus sensors.
Frequently Asked Questions
Does a regen clean ash out of a DPF?
No. Regeneration burns off soot only. Ash stays in the filter until it's removed by an off-vehicle cleaning.
How long does DPF cleaning take?
Our turnaround is 24 hours once your filter arrives at our cleaning plant. EGR cooler cleaning takes 48 hours.
How much does DPF cleaning cost?
DPF cleaning is $300. Add DOC cleaning for $80 when it's cleaned with your DPF. Save $25 on each item when you drop it off and pick it up at our cleaning plant.
Can you clean a cracked or melted DPF?
No. Cleaning can't repair physical damage. We'll contact you if our inspection finds damage before we go further.
Schedule Your DPF Cleaning
Call 574-213-8691 or email dieseldpfcleaning@gmail.com. We're open Monday–Friday, 10 a.m.–5 p.m. Eastern. Have your engine make and model, the filter part number, and any fault codes ready when you call.