DPF Diagnostics & Cleaning

DPF Diagnostics And Cleaning Service

CLEAN IT. DO NOT DELETE IT.

Diesel particulate filter diagnosis, forced regeneration, cleaning and replacement, with the underlying cause found before the filter is touched. We do not remove DPFs, because a car without one is illegal to drive on Irish roads and fails the NCT on sight.

A Blocked DPF Is Usually A Symptom, Not The Disease

The filter is doing exactly what it was designed to do. When it blocks, something has either stopped it regenerating or is filling it faster than it can burn off, and cleaning the filter without finding that something buys you a few months at most.

A leaking injector, a stuck EGR valve, a failing turbo, a dead glow plug, the wrong grade of oil, a faulty pressure or temperature sensor, or a driving pattern that never lets the exhaust get hot enough will all block a DPF. We diagnose the cause first and reports it alongside the cleaning quote, so you know whether you are fixing the problem or renting a few thousand kilometres.

DPF Services We Carry Out

DPF Fault Diagnosis And Pressure Testing

Before anything is cleaned, the filter is assessed properly. Differential pressure across the filter, soot and ash load values read from the ECU, exhaust temperatures and regeneration history together tell us whether this is a blockage, a sensor fault or a filter at the end of its life.

- Differential pressure measurement under load
- Soot load, ash load and distance since last regeneration
- Exhaust gas temperature sensor testing
- Regeneration history and abort reasons read from the ECU

Forced Regeneration

Where the filter is loaded but healthy, a forced regeneration run on the diagnostic equipment burns the soot off under controlled conditions rather than hoping a motorway run does it. There are safe limits to this, and an overloaded filter should not be force regenerated at all.

- Controlled static or dynamic regeneration
- Soot load checked before and after
- Safety limits respected rather than ignored
- Adaptation values reset afterwards

On Car DPF Cleaning

For moderately blocked filters, cleaning chemicals are introduced through the pressure sensor port or the temperature sensor port, dissolving deposits without removing the filter. Quicker and cheaper than off car cleaning where the blockage is not severe.

- Filter cleaned in place
- No exhaust strip down required
- Followed by a regeneration cycle
- Before and after pressure comparison

Off Car Cleaning And De Ashing

Heavily loaded filters come off the car for a proper de ash. Soot burns away during regeneration, but ash does not, and ash is what eventually fills a filter permanently unless it is washed out.

- Filter removed, cleaned and refitted
- Ash flushed out rather than burned
- Substrate inspected for cracking and melting
- New gaskets and clamps on refit

DPF Replacement

Some filters cannot be saved. A cracked or partially melted substrate, usually the result of repeated failed regenerations, has to be replaced rather than cleaned. We will show you the evidence before recommending it.

- Original equipment and quality aftermarket options priced
- Substrate damage assessment before quoting
- Correct coding and adaptation reset after fitting
- Full system leak and pressure check

EGR Valve Cleaning And Replacement

A stuck or leaking EGR valve dumps soot straight into the exhaust and is one of the most common reasons a filter blocks again after cleaning. It is checked as standard on every DPF job here.

- EGR valve, cooler and pipework inspection
- Carbon cleaning and valve replacement
- EGR fault code and flow rate testing
- Intake manifold soot assessment

Symptoms Of A DPF Problem

Caught early, most of these are a diagnostic and a regeneration. Ignored, they become a replacement filter and sometimes an engine.

The DPF Light Comes On

The car is telling you it needs to regenerate and cannot. At this stage a controlled regeneration usually solves it, and the light is not yet an emergency.

Loss Of Power Or Limp Mode

The engine protects itself once back pressure gets too high. Power drops sharply, the car will barely exceed a fixed speed and further regeneration attempts stop.

Regeneration Starts But Never Finishes

Short journeys are the usual cause. Each aborted regeneration adds unburned fuel to the oil and leaves the soot behind, so the problem compounds every time.

The Oil Level Is Rising

Fuel from failed regenerations is diluting the engine oil. This one matters. Diluted oil loses its ability to protect bearings, and on some engines a badly overfilled sump can cause the engine to run on its own oil. Stop driving and get it checked.

A Hot Or Acrid Smell After Driving

Normal during a regeneration, which runs the exhaust extremely hot. Worth knowing about, and worth not parking on dry grass while it happens.

The Cooling Fan Runs Hard After You Switch Off

Often a sign that a regeneration was in progress when you arrived. Repeated interrupted regenerations are the fastest route to a blocked filter.

Stop Start Has Stopped Working

Many vehicles disable stop start during regeneration or when a fault is stored. It is a small clue that something in the exhaust after treatment system is unhappy.

How A DPF Job Works, Stage By Stage

Stage 01

Scan And Pressure Test
Full system scan, soot and ash load values, differential pressure and regeneration history. Our car diagnostics service establishes whether the filter is the problem or the messenger.

Stage 02

Find The Cause, Not Just The Blockage
EGR, injectors, turbo, glow plugs, sensors and oil condition are checked before anything is cleaned, because cleaning a filter behind an unresolved fault is money spent twice.

Stage 03

Quote And Your Approval
You get the readings, the cause, the options and the prices side by side. Nothing is ordered and no work starts until you approve it.

Stage 04

Clean Or Replace, Then Reset And Road Test
The filter is cleaned or replaced, adaptation values and ash counters are reset, and the car is driven to confirm a full regeneration completes properly before it goes back to you.

Let Us Handle The Repairs -- You Focus On The Drive

DPF FAQs

Need a quick answer about your vehicle? Call the garage and speak directly with the team.

How much does DPF cleaning cost?

It depends on whether the filter can be cleaned on the car or has to come off, and on what caused the blockage. CONFIRM: state your diagnostic charge and typical cleaning price range.

Can a blocked DPF always be cleaned, or will it need replacing?

Most can be cleaned. A filter with a cracked or melted substrate cannot, and no amount of cleaning will restore it. We test before recommending either.

Is it legal to remove a DPF in Ireland?

No. Removing a factory fitted DPF is an emissions offence, the car will fail the NCT because testers check the filter is present, and it is a material disclosure issue for your insurer.

Why does my DPF keep blocking after it was cleaned?

Because the cause was never found. A stuck EGR valve, a leaking injector, a failing turbo or a faulty sensor will refill a clean filter within months.

How long does a forced regeneration take?

Usually somewhere between twenty and forty minutes on the equipment, plus diagnostic time before and after. An overloaded filter should not be force regenerated at all.

Book A DPF Check In Dublin

If the DPF light is on, the car has lost power or the oil level is climbing, get it looked at before the filter is beyond saving. The workshop is on Robinhood Road, a few minutes from the M50, with parking on site.