Signs your DPF is blocking
- DPF or exhaust filter warning light, or a 'cleaning exhaust filter' message
- Loss of power and a limp-mode restriction
- Repeated regeneration attempts that never complete
- Higher fuel use and a strong hot smell after driving
- Engine oil level rising from fuel dilution
DPF issues by brand
RAM Cummins
6.7 Cummins DPFs commonly block early due to a leaking EGR cooler, a failing differential pressure sensor, or a pattern of short trips that never let the exhaust reach regeneration temperature.
Silverado & GMC Duramax
Duramax DPF problems are often tied to the DEF/SCR system alongside the filter itself — a NOx sensor or dosing fault can trigger repeated failed regenerations even when the filter itself has capacity left.
Ford Power Stroke
Power Stroke DPFs are sensitive to turbo boost leaks and injector overfuelling, both of which load extra soot into the filter faster than normal driving would produce.
How we clean a DPF
First we read live differential pressure and soot-load data to confirm the filter is actually the problem. If the filter can still regenerate, we run a service regeneration. If it is loaded with ash rather than soot, regeneration will not save it — we remove and machine-clean the filter, then re-test the pressures against specification.
Forced regeneration vs machine cleaning
| Forced (service) regeneration | Machine (removed) cleaning | |
|---|---|---|
| Fixes | Soot buildup, filter still within capacity | Ash buildup or a fully blocked filter |
| Time on the truck | Under an hour typically | Filter removed, several hours |
| Works when regeneration keeps failing | No — that's the sign it won't help | Yes |
Fixing the cause, not the symptom
A DPF that blocks early is telling you something else is wrong: a leaking EGR cooler, a failed differential pressure sensor, injector overfuelling, a turbo actuator that will not hold boost, or simply a truck that only does short trips. We diagnose the cause during the same visit so you are not back in three months.
How long does it take and what does it cost
A straightforward forced regeneration can be completed in under an hour. Removing and machine-cleaning a filter, plus diagnosing and repairing the underlying cause, takes considerably longer and is quoted on enquiry once we've confirmed what's actually needed.
Short trips, towing and Queensland driving patterns
Trucks used mostly for short local trips around Caloundra rarely get the exhaust hot enough for the truck to complete its own automatic regeneration, which is one of the most common causes of DPF problems we see — not a faulty part at all. Conversely, trucks that tow long distances at sustained highway speed regenerate well but load the filter faster with soot in the first place, so both use patterns benefit from periodic checks.
We do not delete or bypass emissions equipment. It is illegal for road-registered vehicles in Queensland and it destroys resale value.
Frequently asked questions
- Can you clean a DPF without removing it?
- Sometimes. If the filter still regenerates we can run a forced regeneration on the workshop floor. Ash-loaded filters have to come off for machine cleaning.
- Why does my truck keep going into regeneration?
- Usually short trips, or a fault feeding extra soot into the filter — EGR, injectors or a boost leak. Live data tells us which.
- Do you delete DPFs?
- No. Emissions deletes are illegal on registered vehicles and void warranty. We repair the system properly instead.
- How much does DPF cleaning cost?
- It depends on whether the filter needs a forced regeneration or full removal and machine cleaning, plus any underlying repair needed, so it's quoted on enquiry once we've diagnosed the cause.
- How often should a DPF be cleaned?
- A healthy system should self-regenerate automatically during normal driving and rarely need intervention. If you're seeing repeated warnings every few weeks, that's a sign of an underlying fault rather than something to just keep clearing.
- Is it legal to remove my DPF in Australia?
- No. Removing or deleting a DPF on a road-registered diesel vehicle is illegal in Queensland and across Australia, and it will fail a roadworthy inspection. We repair emissions systems rather than delete them.
- Can I drive with a blocked DPF warning light on?
- You can usually drive short distances at reduced power, but continuing to drive with the light on risks the truck dropping into a more restrictive limp mode or causing further damage — it's best diagnosed promptly.
- What causes repeated regeneration failures on a RAM Cummins?
- Common causes are a leaking EGR cooler, a faulty differential pressure sensor, or short-trip driving that never lets the exhaust reach regeneration temperature. We test each of these rather than assuming the filter itself is the fault.